Translate the following sentences into English using the participle.

1. Ми спостерігали, як хлопці грали в футбол.

2. Я бачила, як діти пили чай.

3. Оскільки вітер дув з півночі, було дуже холодно.

4. Коли лист був написаний, я відніс його на пошту.

5. Вони чули, як її батько розмовляв німецькою мовою.

6. Оскільки вчитель був хворий, у нас вчора не було уроку фізики.

7. Ми бачили, як він сідав у трамвай.

8. Студенти, що працюють у нашому селі, прибули з Києва.

9. Після того, як посилку запакували, її віднесли на пошту.

10. Коли батько прийшов, усі сіли за стіл обідати.

10. Choose the correct verb forms (-ing form or Infinitive). If two answers are possible, put both.

1. Do you remember (meet) her last year?

2. Sorry – I forgot (post) your letters.

3. I regret (not visit) her when she was ill.

4. We discussed the budget and then went on (talk) about sales.

5. Do you want to go on (learn) English?

6. He doesn't allow us (make) personal phone calls.

7. The hospital only allows (visit) at weekends.

8. I like (watch) TV in the evenings.

9. Would you like (spend) the weekend with us?

10. Thanks – I’d love (come).

II семестр

Baріант № 2

Read and translate the text.

FRICTION

When you try to walk on ice, slipping and sliding and perhaps falling down, you realize the importance of friction. Ice has a low coefficient of friction and that is what makes it so difficult to walk on. Without friction it would be impossible to walk at all and our trains and cars could not move.

There are three different kinds of mechanical friction: static, sliding, and rolling. Static friction is the resistance to motion between two bodies in contact but at rest. The resistance of static friction is greater than that of sliding friction which is resistance to continued motion after one body has started to move. Rolling friction occurs when resistance is reduced to its lowest degree by rotary motion not on the same axis. Note these three kinds of friction at work: it takes a stronger effort to put a box into motion (static friction) then it does to keep it moving across the floor once started (sliding friction); if there are rollers under the box it takes still less effort to keep it in motion (rolling friction).

One way to reduce friction in machines is through the materials for the parts that contact each other. The coefficient of friction is the constant ratio of the friction to the force pressing the surfaces together. Coefficients have been equated for different common materials using the three types of friction. Steel on steel or glass on glass have high coefficients but some new substances have much lower coefficients. One of these is Babbitt metal, an alloy made of tin, copper, and antimony; another is Teflon, a plastic containing fluorine that is sometimes used in cooking utensils.

Another way of reducing friction is by means of lubrication, applying oil or grease to the points or surfaces where the parts of a machine contact each other. Petroleum products are the principal modern lubricants; some of them include polymers, the long, heavy, complex molecules that occur in plastics. A vital mechanism for reducing friction is the bearing which basically is a device that bears the friction of parts in motion.

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