2. Complete the following sentences using the modal verbs from the text:

1. You __________ obey laboratory rules while working there.

2. Students _________ come on time and ____________ disturb others by being late.

3. You _________ come if you __________ be on time.

4. If you don’t complete the lab, you _________ complete the lecture.

5. You ___________ eat, drink or smoke in the laboratory.

6. Students __________ leave their working place tidy.

7. Long hair _________ be tied back.

8. Baggy clothes ___________ be worn because they ____________ catch fire.

9. If you _________ smell the fumes, you ___________ report immediately.

3. Discuss in pairs which modals from the text are used to express:

obligation, negative obligation, no obligation, permission, recommendation, ability, inability

Grammar (1):

Modal verbs of obligation: must/mustn’t, have to/ don’t have to, should/ shouldn’t

must (должен)

- for obligation (which is the speaker’s opinion) I must call him today.

- for strong recommendations You must see this film.

mustn’t (нельзя)

- not allowed, you can’t You mustn’t park here.

have to (нужно, придётся)

- for external obligation, laws, or rules You have to drive on the left.

don’t have to (не нужно, нет необходимости)

- for no obligation or necessity We don’t have to work on Sundays.

should / ought to (следует) You should drive more slowly.

shouldn’t / oughtn’t to (не следует) .

- for recommendations , advice

1. Read the following sentences and translate them into Russian.

I

should must have to

take my computer to the service centre.

2. Make the sentences from exercise 1 negative.

3. Transform them into questions.

4. Transform them into the third person singular (he/she/it) affirmative, negative, questions.

5. Translate the sentences into Russian. Explain the use of the verb have.

1. Never spend money before you have it.

2. We have to obey the lab safety rules.

3. Overdocumentation has two dangers.

4. They have had many assistants.

5. Recent experiments have produced conflicting results.

6. They must be able to identify the particular error that has occurred in the input.

7. Someone had to confirm that light travels at a finite speed.

6. Match the “heads and tails”.

You shouldn’t take antibiotics	because it can evaporate.
You should ask the supervisor some advice	it may cause damage to the monitor.
You don’t have to switch off the engine	because you can surf the Internet.
You don’t have to go to the library	if the doctor hasn’t prescribed them.
You mustn’t keep this substance in the open dish	if you stop at the traffic lights.
You mustn’t install the monitor close to the electric heater because	when you can’t do the lab work.

7. Complete the sentences with must or have to in the correct form. Sometimes it is possible to use either.

1. You really… work harder if you want to pass that examination. 2. Last night he suddenly became ill. We… call the doctor. 3. She … wear glasses since she was eight years old. 4. I’m afraid I can’t come tomorrow. I… work late. 5. I’m sorry I couldn’t come yesterday. I…work late. 6. We couldn’t repair the car ourselves. We…take it to a garage. 7. When you come to London again, you…come and see us. 8. It’s 10 o’clock. I…go now.