Учебное пособие для химических специальностей итф: Учебн пособ./ англ яз. Н. С. Иванова, Р. С. Карпеева. Самара



страница1/5
Дата22.06.2019
Размер0.6 Mb.
ТипУчебное пособие
  1   2   3   4   5




ФЕДЕРАЛЬНОЕ АГЕНТСТВО ПО ОБРАЗОВАНИЮ

государственное образовательное учреждение

высшего профессионального образования

“Самарский Государственный технический университет”



Кафедра иностранных языков

Н.С. ИВАНОВА,

Р.С. КАРПЕЕВА

Chemical Laboratory Safety
Учебное пособие

Самара


Самарский государственный технический университет

2011


Н.С.ИВАНОВА, Р.C.КАРПЕЕВА

Chemical Laboratory Safety. Учебное пособие для химических специальностей ИТФ

Пособие содержит 10 текстов. Даются грамматические и лексические упражнения, необходимые для формирования навыков чтения научно-технической литературы, а также разговорных навыков. Прилагаются грамматический справочник, список неправильных глаголов, список слов и словосочетаний, часто встречающихся в научно-технической литературе. Данные пособие может быть использовано преподавателями английского языка при работе со студентами II курса инженерно-технологического факультета.
Печатается по решению редакционно-издательского совета Самарского государственного технического университета.
УДК 811.111(075.8)

ББК Ш13Англ-923


Н.С.ИВАНОВА, Р.С.КАРПЕЕВА;

Chemical Laboratory Safety Учебное пособие для химических специальностей ИТФ: Учебн. пособ./ англ. яз .Н.С.ИВАНОВА, Р.С.КАРПЕЕВА.-Самара:

Самар.гос. техн. ун-т, 2011. 67с.
Техника безопасности в химической лаборатории. Пособие содержит 10 текстов на англ. яз. Даются грамматические и лексические упражнения, необходимые для формирования навыков чтения научно- технической литературы, а также разговорных навыков. Прилагается грамматический справочник, список слов и словосочетаний часто встречающихся в научно- технической литературе.

Учебное пособие предназначено для студентов второго курса ИТФ СамГТУ.


Рецензент:

кандидат филологических наук, доцент Т.А.Филоненко

Н.С.Иванова, Р.С.Карпеева, 2011

Самарский государственный

технический университет, 2011


Настоящее пособие предназначено для обучения чтению и навыкам разговорной речи студентов химических специальностей II курса ИТФ и разработано на основе специально – ориентированных текстов. В качестве текстов взята инструкция по технике безопасности при работе в химической лаборатории QUEEN’S University, Канада. Тексты частично адаптированы и сокращены.

Постоянное расширение международных контактов в области науки и техники привело к необходимости подготовки специалистов, умеющих самостоятельно работать со специальной литературой на иностранном языке и способных к деловому общению. Данное пособие составлено с целью подготовки и адаптации специалистов-химиков в профессиональной иноязычной среде. Это достигается выбором текстов и комплексом упражнений. Пособие может использоваться как для аудиторной так и для внеаудиторной работы.

. В пособии предлагаются тексты и упражнения, направленные на развитие навыков чтения, а также формирование речевых навыков. В каждом разделе Упр.1 знакомят студентов с определенными грамматическими явлениями, которые далее иллюстрируются текстами данного раздела, а в Упр.2 выбрана частотная лексика по данной специальности. Таким образом, освоение студентами грамматики, синтаксиса, словообразования, сочетаемости слов, а также активное усвоение наиболее употребительной лексики и фразеологии изучаемого языка происходит в процессе работы над связными, законченными в смысловом отношении произведениями речи.

В работе широко используются активные методы обучения, которые направлены на достижение продуктивного уровня усвоения знаний. Это происходит за счет выполнения различных лексических и грамматических заданий и использования изученного материала в игровых ситуациях, имитирующих реальные ситуации общения, которые могут возникнуть в профессиональной деятельности. Так, студентам предлагается рассказать, что должен знать о мерах безопасности человек, впервые пришедший работать в химическую лабораторию, как должен вести себя получивший травмы, обсуждаются наиболее опасные химические вещества, способы их хранения и особенности работы сними.

Пособие содержит 10 тематических разделов. Даются грамматические и лексические упражнения, необходимые для формирования навыков чтения научно-технической литературы. Прилагаются грамматический справочник, список неправильных глаголов, список слов и словосочетаний, часто встречающихся в научно-технической литературе.
Unit 1.

The Passive voice.
Ex. 1. Read the sentences, find the predicate and the subject, define the tense and the voice of the predicate. Translate the sentences from English into Russian.


  1. Charged particles are influenced by electric fields.

  2. It was found that the substance was radioactive.

  3. The result of the experiment is shown in fig. 11.

  4. The new discovery was much being spoken about.

  5. This problem can be solved by a new kind of electronic computers.

  6. The performance of the new computer will be demonstrated tomorrow.

  7. The molecules of even a good insulator are acted upon by an electric field.

  8. The operation of the new device was looked at with great interest.

  9. This manual covers many of the common or general hazards which are associated with work in the Department. and must be read by everyone working in the Department.

  10. Additional information or measures may be required.

  11. The responsibility of individual supervisors is to ensure that the necessary procedures and protocols are both established and followed in their respective work areas.

  12. Most health and safety problems in the laboratory can be avoided by practicing good housekeeping and common sense.

  13. A safe working environment is achieved through responsible and motivated activity.

  14. Every person working at the Department should know and follow safety rules as well as procedures which have been established.

  15. Fire doors must be kept closed at all times; automatic (self-closing) fire doors must not be blocked.

Ex.2a) Read the following reference information.

first aid kit-медицинская аптечка

housekeeping-содержание рабочего места

Ex.2b). Find the following active words and expressions in the text, choose the right Russian equivalents from the dictionary . Learn these active words and expressions.



safety

responsibility

staff

researcher



manual

hazard


measure

appropriate

source

supervisor



ensure

establish

follow

depend on\upon



perform

be aware

deal with

exit


fire extinguisher

fire alarm

first aid kit

equipment

available



Ex. 3 Read the text.
Safety
Safety is the responsibility of everyone who works in the Department: all faculty, staff, graduate students, researchers and visitors to the Department are included. This manual covers many of the common or general hazards which are associated with work in the Department and must be read by everyone working in the Department. It cannot be assumed that the warnings or rules laid out in this manual are necessarily complete for dealing with specific chemical or physical hazards; additional information or measures may be required and the appropriate information sources should be consulted.

The responsibility of individual supervisors is to ensure that the necessary procedures and protocols are both established and followed in their respective work areas. The responsibility of workers is to follow prescribed procedures and protocols when they deal with hazards in the laboratory.

Personal safety depends upon a positive attitude towards safety as well as good, informed judgment on the part of each individual working in the Department. Most health and safety problems in the laboratory can be avoided by practicing good housekeeping and common sense based upon informed knowledge of the hazards. A safe working environment is achieved through responsible and motivated activity.

General department safety

Every person working at the Department should know and follow safety rules as well as procedures which have been established, and be aware of hazards and the procedures for dealing with those hazards, before he starts his work. One should familiarize himself with all safety equipment and procedures in his work area (telephone, exits, fire extinguishers, fire alarms, safety shower, eyewash fountain, first aid kit, evacuation routes).

Fire doors must be kept closed at all times; automatic (self-closing) fire doors must not be blocked. Never block emergency exits, emergency equipment or electrical panels. Maintain a tidy workplace. Research labs must keep lab doors closed to effect proper ventilation of the lab.

Working Alone

Undergraduate students must not work alone in a laboratory at any time. A second person must be present and must assume responsibility for supervision of the undergraduate. The work carried out must be authorized by a faculty member.

For other members of the Department, working alone is usually defined as working in a laboratory outside of normal working hours (8 a.m. to 6 p.m., Monday through Friday) in the absence of any other co-workers. Individuals may work alone if their laboratory work is of a non-hazardous nature and if there is someone else working on the same floor of the building.

If, for some reason, hazardous work must be performed outside normal working hours then the work must have your supervisor’s approval, a second co-worker must be available in case of emergency.


Ex. 4. Answer the following questions.


  1. Who is responsible for safety in the Department?

  2. What is the responsibility of individual supervisors?

  3. What is the responsibility of workers?

  4. What does the personal safety depend on?

  5. How can most health and safety problems be avoided?

  6. What helps to achieve a safe working environment?

  7. What must every person know and do before he starts his work?

  8. What should you know about fire doors and emergency equipment?

  9. What rules should be followed while working alone?

  10. Under what conditions may individuals work alone?

Ex. 5. Are the following sentences true or false?



  1. Safety is the responsibility of the staff of the Department only.

  2. Most health and safety problems in the laboratory can be avoided.

  3. Every person working in the Department should familiarize himself with all safety equipment and procedures in his work area.

  4. Research labs mustn’t keep lab doors closed.

  5. Undergraduate students may work alone in a laboratory at any time.

Ex. 6. Find international words in the text, give their Russian equivalents.


Ex. 7. Find the derivatives of the following words in the text, define what part of speech they belong to and give their translation.

to work, to deal with, to inform, safe, to graduate, hazard, to equip, responsible, person


Ex. 8 Find all the words which end in“-s”. Define if they are plural nouns or singular verbs.
Ex. 9. Find all the words which end in“-ed”. Define if they are verbs in Past Simple or ParticipleII .
Ex. 10. Find all the sentences with modal verbs and translate them into Russian.
Ex. 11 Find the key words in the text and translate them.
Ex. 12. You are a first-year student who comes to the laboratory for the first time. Tell us what you are to know about the safety before you start your work. Use the key words from the text .

Unit 2

Participle I / Participle II. (attribute)
Ex. 1. Read the sentences, find the predicate and the subject, define the tense and the voice of the predicate. Find Participle I and Participle II. Translate the sentences from English into Russian.


  1. Electrons forming an atom are in motion.

  2. The latest model now being tested accounts for many of the previously unknown phenomena.

  3. An equation describing the depolarization of the fluorescence has been developed.

  4. For the investigation being conducted at present the lack of such data is of no importance.

  5. The acceleration of a body is proportional to the force causing it.

  6. The nucleus formed by the emission of the gamma-ray may be unstable.

  7. The equipment needed for the experiment was carefully checked.

  8. For further details you can read the paper presented by Brown.

  9. Our attention will be focused on comparative methods applied by different sciences.

  10. The ions thus formed will be accelerated in the direction towards the cathode.

  11. Minor accidents involving hazardous chemicals or the malfunction and/or breakdown of equipment must be reported to your supervisor.

  12. All accidents involving personal injury must be reported promptly to your supervisor.

  13. The injured person must be sent or taken to the hospital emergency room, or doctor.

  14. A severely injured person must not be moved without the advice of medical or ambulance personnel.

  15. Do not touch anything associated with the accident.

Ex.2a) Read the following reference information.

hospital emergency room-отделение неотложной помощи

Ex.2b). Find the following active words in the text, choose the right Russian equivalents from the dictionary . Learn these active words.


accident

involve


malfunction

breakdown

injury

treat


severe

doubt


emergency
advice

indicate


location

lead


touch

except for

purpose

suffer


examine

Ex. 3. Read the text.
Reporting of accidents

Minor accidents involving hazardous chemicals or the malfunction and/or breakdown of equipment must be reported to your supervisor. More serious accidents must be reported to the Head of the Department and/or the Department Safety Officer as well as to your supervisor. All accidents involving personal injury must be reported promptly to your supervisor who is responsible for ensuring that the procedures below are followed. If your supervisor is not immediately available, contact the Head of the Department.

Apply first aid (first aid kits should be available in all labs); first aid should be given by someone who has had appropriate training. In the case of minor injuries that cannot be satisfactorily treated by first aid alone, or if there is any doubt, the injured person must be sent or taken to the hospital emergency room, or doctor.

In the case of injuries that are more severe, or there is doubt about the severity of the injury, and emergency assistance is required, call 03. A severely injured person must not be moved without the advice of medical or ambulance personnel.

If it is necessary to call an ambulance, indicate the location of the injured person and the location of the nearest appropriate entrance to the building. If possible send someone to that entrance to lead the ambulance personnel to the person injured.

For all accidents involving critical injury or death you are to notify your supervisor, the Head of the Department (or Safety Officer) as soon as possible. Do not touch anything associated with the accident, except for the purpose of saving life, relieving suffering, or preventing unnecessary damage to equipment or property. The scene of an accident must be examined by the appropriate authorities.


Ex.4. Answer the following questions.



  1. Who must minor accidents or malfunctions be reported to?

  2. Who must more serious accidents be reported to?

  3. What accidents must be reported to your supervisor who is responsible for ensuring the procedures?

  4. Who do you contact if your supervisor is not immediately available?

  5. What should be available in all labs?

  6. When must the injured person be taken to the hospital emergency room?

  7. Must a severely injured person be moved?

  8. What should be done if it is necessary to call an ambulance?

  9. Who must you notify about the accidents involving critical injury or death as soon as possible?

  10. Is it possible to touch anything associated with the accident?

Ex.5. Find the derivatives of the words “injury’’ and ‘’severity” in the text, define what part of speech they belong to, and give their translation. Then find and translate all word combinations with them.


Ex.6. Find international words in the text, give their Russian equivalents.
Ex.7. Imagine: you have minor injuries.

What must you do?

What don’t you have to do?

Ex.8. Answer the topical questions.



  1. Must the scene of an accident be examined immediately? Why?

  2. What would you do if you were alone in the lab where an accident has just happened?

  3. Could you apply first aid in case of emergency?

  4. Have you had the appropriate training for applying first aid?

  5. When and where did you have it?

Ex.9. Retell the text paying attention to the actions to be done while reporting of accidents
Ex.10. Role play.

Make up a dialogue between a person who has minor injuries and his fellow-student after the accident in the lab.


Unit 3.

Participle I / Participle II. (adverbial modifier)
Ex. 1. Read the sentences, find the predicate and the subject, define the tense and the voice of the predicate. Find Participle I and Participle II. Translate the sentences from English into Russian.


  1. While explaining the results of the experiment the professor wrote a lot of formulae on the blackboard.

  2. While being used the device showed poor characteristics.

  3. While repairing the motor the operator found two broken parts.

  4. Using the energy of the atom we produce electric energy at atomic power plants.

  5. Reacting with a base an acid gives rise to a salt and water.

  6. When calculating the weight of a body we have to multiply its specific gravity by its volume.

  7. The iodine ion is easily oxidized, being changed to free iodine by many agents.

  8. When arranged properly the device works without breakdowns.

  9. When properly insulated the wire may be used in conditions of excessive moisture.

  10. Being heated for a long time the liquid becomes viscous.

  11. Working with strong acids and bases, and other corrosive substances use appropriate personal protective equipment and fumehood ventilation.

  12. Wear appropriate safety goggles or splash shields when working with corrosive substances.

  13. When handled, some specific acids such as HF (extremely toxic) require special procedures.

  14. The minimum temperature at which vapours from a substance will ignite in air when exposed to an ignition source is called the flash point.

  15. Always connect (or bond) containers when transferring flammable liquids from metal containers.

Ex.2a) Read the following reference information.

HF (hydrofluoric acid)-фтористоводородная кислота

Br (bromine)-бром

reducing agent-восстановитель

cabinet-шкаф

reflux-обратный поток

approved-соответствующий требованиям безопасности

Ex.2.b) Find the following active words in the text, choose the right Russian equivalents from the dictionary . Learn these active words



substance

property


investigate

reducing agent

oxidizing agent

acid


compound

fumehood


flammability

solvent


vapour

ignite


expose

spark


heat

combustible

liquid

volume


amount

connect


transfer

reflux


pressure

Ex.3. Read the text.



Chemical Laboratory Safety

There are over 10 million known chemical substances with more being continually discovered; the hazardous properties of most of these substances have not been investigated. There are, however, many classes of compounds that present certain hazards such as oxidizing agents and reducing agents, corrosives such as acids and bases, water reactive chemicals, air reactive chemicals, self-reactive chemicals, highly toxic chemicals.

This manual will describe general procedures and protocols for dealing with common hazards in the chemical laboratory.

General Chemical Hazards

Corrosivity

Corrosive chemicals cause visible destruction or irreversible alteration to living tissue.

Common acids and bases are the most common corrosives encountered, but other chemicals, such as Br, are also extremely corrosive. Concentrated acids and bases should always be diluted by addition to water due to the large heat of solution for these compounds.

Working with strong acids and bases, and other corrosive substances use appropriate personal protective equipment and fumehood ventilation.

Safety glasses do not provide complete eye protection from chemical splashes; wear appropriate safety goggles or splash shields when working with corrosive substances.

NOTE: when handled, some specific acids such as HF (extremely toxic) require special procedures. Consult the appropriate references and your supervisor before working with these chemicals.



Flammability

The risk of fire in the chemical laboratory is most often associated with two classes of compounds - common organic solvents, and certain metals, metal hydrides and organometallics. The following should be noted for common organic solvents: the minimum temperature at which vapours from a substance will ignite in air when exposed to an ignition source (flame, spark, static discharge, etc.) is called the flash point. A flammable substance has a flash point below 37.8°C. A combustible substance must be heated at or above 37.8°C to ignite. Bottles of flammable liquids up to 1L in size can be stored anywhere in laboratories; larger quantities must be stored in flammable storage cabinets (e.g. 4L bottles) or in approved safety containers. The maximum volume of (flammable + combustible) liquids that may be stored in the open lab is 300 liters; the maximum allowable amount of flammable solvents is 50 of the 300 liters. Flammable waste solvents cannot be collected in the open lab in containers larger than 1 liter capacity. Always use ventilation (e.g. fumehoods) which is adequate for the quantity of flammable liquid in use. Always connect (or bond) containers when transferring flammable liquids from metal containers. Only refrigerators/freezers that are approved for flammable storage can be used in laboratories.

The Department of Chemistry also has standard operating procedures for operations involving the distillation and reflux of flammable liquids at atmospheric pressure in fumehoods.

Ex.4. Answer the following questions




  1. How many chemical substances are known?

  2. Have the hazardous properties of all the substances been investigated?

  3. Are there any classes of compounds that present certain hazards? What are they?

  4. What is the risk of fire in the chemical laboratory most often associated with?

  5. What are the ignition sourсes?

  6. What is called the flash point?

  7. What is the flash point of a flammable substance?

  8. Where can bottles of flammable liquids up to 1L in size be stored?

  9. Where must larger quantities of flammable liquids be stored?

  10. What is the maximum volume of (flammable + combustible) liquids that may be stored in the open lab?

  11. What is the maximum allowable amount of flammable solvents?

  12. How can flammable waste solvents be collected?

  13. What kind of ventilation should be used?

  14. What kind of refrigerators / freezers can be used?

Ex.5. Complete the table with the derivatives from the text.



verb

noun

adjective/participle II







ignited

to ventilate










protection










hazardous

Ex.6. Match the following word combinations with their Russian equivalents.

1) hazardous properties 2) certain hazard 3) common hazard

a)определенный риск, b)опасные свойства, c)распространенная опасность.


Ex.7. Explain the difference between such terms as ‘’flammable’’ and ‘’combustible’’. Match the words with their definitions.

a) easily set on fire , b) capable of burning


Ex.8. Discuss these topical questions.


  1. Do you know that common organic solvents, metal hydrides, organometallics are the most dangerous chemical substances for the chemical laboratory? Why?

  2. What rules do you recommend to follow while working in the chemical laboratory?

Ex.9. Imagine that you are the Head of the Chemical laboratory. Give instructions to the newcomers.


Ex.10 Mini role-play.

You are at the exam. The teacher is asking a student questions about the risk of fire in the chemical laboratory. Answer these questions.

You may use the following questions: 1.What classes of compounds present certain hazards?

2. What do corrosive chemicals cause?

3. What are the most common corrosives?

4. What other chemicals are also extremely corrosive?

5. How should concentrated acids and bases be stored?

6. What protective equipment should be used? etc.


Unit 4.

/ Participle I / Participle II. (attribute/adverbial modifier)
Ex. 1. Read the sentences, find the predicate and the subject, define the tense and the voice of the predicate. Find Participle I and Participle II. Translate the sentences from English into Russian.


  1. When heated water boils.

  2. The algorithm chosen in this study is a simplified version of Wagner’s model.

  3. The results obtained showed the stability of the system.

  4. Every body located on earth is pulled downwards by the earth.

  5. The signal supplied by the auxiliary source controls the power.

  6. The temperature of the liquid obtained remained constant.

  7. All the isotopes now produced by reactors can also be made in a cyclotron.

  8. One of the most striking properties of water is its ability to dissolve many substances, forming aqueous solutions.

  9. The phenomenon influencing the rate of the reaction was thoroughly investigated.

  10. Water is the most efficient agent, having a high heat transfer coefficient and a high heat capacity.

  11. The following rules should be noted when working with this class of compounds.

  12. Use equipment appropriate for the hazards associated with such substances as metal hydrides and organometallic compounds.

  13. Metals in a finely divided form can ignite on exposure to air and/or water.

  14. Thiols and related sulfur-containing compounds are characterized by a particularly noxious odour.

15. Substances reacting with moisture in the eyes and mucous membranes cause tear formation and must be stored in well sealed containers.

. Ex.2a) Read the following reference information.

metal fire-металлическое зажигательное вещество

lachrymators-слезогонные вещества

mucous membrane-слизистая оболочка

Ex.2b). Find the following active words in the text, choose the right Russian equivalents from the dictionary . Learn these active words.



alkali

separate


inert

technique

noxious

sulfur


contain

particularly

odour

release


consequently

in advance of

storage

disposal


friction

sensitive

violently

moisture


cause

ester


seal

shock

Ex.3. Read the text.

General Chemical Hazards.
Alkali and alkaline earth metals, certain other metals such as aluminum, metals in a finely divided form, metal hydrides and many organometallic compounds can ignite on exposure to air and/or water. The following rules should be noted when working with this class of compounds:

• store these chemicals in a location separate from other chemicals in the laboratory and in containers appropriate for the purpose

• use equipment appropriate for the hazards associated with these substances including inert atmosphere techniques

• class “D” fire extinguishers (metal fires) must be present in laboratories where these substances are in use;

• do not use “C” class fire extinguishers (CO2) on metal fires

Noxious Chemicals

Certain classes of compounds such as thiols (mercaptans) and related sulfur-containing compounds are characterized by a particularly noxious odour .These compounds must be used with adequate ventilation (fumehoods). Whenever compounds of this type are used they will be released through the ventilation system into the local atmosphere, consequently both the Department Safety Officer and the Emergency Report Centre must be notified in advance of the use of these chemicals.



Reactive Chemicals (Air/Water Reactive)

There are chemicals which can ignite on exposure to air or water, e.g. certain metallic and organometallic substances. Special handling, storage and disposal procedures must be established in laboratories where these substances are in use.



Self-Reactive Chemicals

Self-reactive chemicals may be heat, shock or friction sensitive and can react violently as a consequence, e.g. acetylene and acetylides, azides, diazonium salts, nitro compounds, chlorates and perchlorates, peroxides

Special handling, storage and disposal procedures must be established in laboratories where these substances are in use

Lachrymators

Substances which react with moisture in the eyes and mucous membranes and cause tear formation, e.g. halogenated aldehydes, ketones and esters must be used with adequate ventilation (fumehood) and stored in well sealed containers.
Ex.4. Answer the following questions.


  1. What chemical substances can ignite on exposure to air?

  2. What chemical substances can ignite on exposure to water?

  3. Where must these substances be stored?

  4. What equipment should be used for the chemicals which can ignite on exposure to air and/ or water?

  5. What kind of fire extinguishers must be present in the laboratory?

  6. What compounds are characterized by a particularly noxious odour?

  7. Who must be notified in advance of the use of these chemicals?

  8. What is special in using these compounds?

  9. What must be established in laboratories where these substances are in use?

  10. What substances must be used with adequate ventilations?

Ex.5. Find the English equivalents to these Russian chemical terms.

1) ацетилен, 2) азид/соль азотоводородной кислоты, 3) соль диазония, 4) соединение, содержащее нитро-группу, 5) хлорат/соль хлорноватой кислоты, 6)перхлорат/соль хлорной кислоты, 7)перекись, 8) тиол (SH), 9) меркаптан (PSH), 10) ацетиленид/карбид.
Ex.6. What other chemical terms are used in the text?
Ex.7.Match the words with their synonyms

1. to accumulate, 2 to apply,3. to contain, 4 to divide, 5 to liberate, 6.to inform.

a) to include b) to separate c) to store d) to use e) to release f) to notify
Ex.8. Retell the text paying special attention to the fact what rules should be noted when working with the compounds which can ignite on exposure to air/ or water.
Ex.9. Mini role-play.
You are an inspector. Ask the person responsible for chemical laboratory safety about measures when working with compounds that can ignite on exposure to air/ or water.

Make up a dialogue using the following questions:

How do you store the chemicals which can ignite on exposure to air/ or water?

What equipment do you use?

What fire extinguishes do you have? etc.
Unit 5.




Поделитесь с Вашими друзьями:
  1   2   3   4   5


База данных защищена авторским правом ©vossta.ru 2019
обратиться к администрации

    Главная страница