Вариант III

1. Перепишите следующие предложения, определите в каждом из них видо-временную форму и залог глагола-сказуемого, укажите инфинитив. Переведите предложения.

1. Machine parts are subjected to x-ray examination.

2. We were shown a number of experiments illustrating the presence of high-energy particles in the cosmic radiation.

3. Many power plants are being built in our country.

4. The atomic power has been applied to all fields of man’s civilian activity.

2. Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения глаголов to be, to have, to do.

1. Some substances do not conduct heat.

2. These computers will have to perform millions of operations per second.

3. Mechanization is to be distinguished from more primitive tool using.

4. Metals conduct electricity better than semiconductors do.

3. Перепишите предложения и переведите их на русский язык, обращая внимание на функцию инфинитива.

1. It is often possible to build a compound directly from its elements.

2. He spoke about the plan to increase the production of the plant.

3. To master this speciality is not an easy thing.

4. Our idea was to design a new device for automatic control.

4. Перепишите и письменно переведите на русский язык следующие предложения. Помните, что объектный и субъектный инфинитивные обороты соответствуют придаточным предложениям.

1. The development of science and technology is known to be the most important source of the steady growth of the people’s well-being.

2. I consider them to be good specialists.

3. These phenomena are believed to be interdependent.

4. We know many human activities to have played a part in scientific inventions.

5. Перепишите и письменно переведите на русский язык следующие предложения, обращая внимание на разные значения слов it, that, one.

1. Reading in a foreign language one often comes across unfamiliar words and expressions.

2. The properties of a composite matter are always quite different from those of the elements it consists of.

3. One of the greatest problems thrown up by our era is that of outer space.

4. It is necessary to find new sources of cheap energy.

VI. Перепишите предложения и переведите их на русский язык, обращая

внимание на различные значения выделенных слов.

1. The visible side of the moon has been studied ever since Galileo invented the telescope.

2. In the year 2020 we will most likely use televisions to interact with the world as we do now with the telephones.

3. Elements are transformed into other elements both by man and nature.

4. I can either come or ring you up.

VII. Прочитайте, перепишите и письменно переведите текст.

Bearings

A bearing is a mechanical device for decreasing friction in a machine in which a moving part bears-that is, slides or rolls on another part. Usually a bearing confines the motion of a part and prevents it from moving in any other way. The common bearings are found at the rigid supports of rotating shafts where friction is the greatest. That part of a shaft which rotates in a bearing is called a journal (1) and the outer portion is a sleeve (2).

Bearings were invented early in history; when the wheel was invented, it was mounted on an axle, and where the wheel and axle touched was a bearing. Such early bearings had surfaces of wood or leather lubricated with animal fat.

Modern bearings have been designated (3) as friction and antifriction bearings.

The first type comprises sleeve or journal bearings.; the second, ball and roller bearings (4). Neither type of bearings is completely frictionless, and both are highly efficient in reducing friction.

Bearing materials must have sufficient strength. They must be good conductors of heat, uniform in structure, resistant to abrasion, and have a low coefficient of friction when dry or slightly greasy. Steel, cast iron and various alloys are commonly used as bearing materials. Lubrication is necessary to reduce the frictional contact between the rolling members and the rotating cages (5), to help to dissipate the heat, otherwise the bearing may “seize”.

Gears

A gear is a toothed wheel or cylinder used to transmit rotary or reciprocating motion from one part of a machine to another. Two or more gears, transmitting motion from one shaft to another, constitute a gear train (6). Gearing (7) is a term used to describe systems of wheels or cylinders with meshing teeth (8).

The simplest gear is the spur gear (9), a wheel with teeth cut across its edge parallel to the axis. Spur gears transmit rotating motion between two shafts or other parts with parallel axes. In simple spur gearing, the driven shaft revolves in the opposite direction to the driving shaft. If rotation in the same direction is desired, an idler gear (10), is placed between the driving gear (11) and the driven gear. In any form of gearing the speed of the driven shaft depends on the number of teeth in each gear.

Bevel gears (12) are employed to transmit rotation between shafts that do not have parallel axes. These gears have cone-shaped bodies and straight teeth.

Helical gears (13) have teeth that are not parallel to the axis of the shaft, but are spiralled around the shaft in the form of a helix. Such gears are suitable for heavy loads because the gear teeth come together at an acute angle rather than (14) at 90˚ as in spur gearing.

Worm gearing is a variation of helical gearing. A worm gear (13) is a long, thin cylinder that has one or more continuous helical teeth that mesh with a helical, gear. Worm gears are used chiefly to transmit rotation, with a large reduction in speed, from one shaft to another at a 90˚ angle.

Пояснения к тексту:

1. a journal – цапфа, шейка вала, пята

2. a sleeve – втулка, полый вал, муфта, штуцер, ниппель

3. to designate [dezigneit]- определять, обозначать

4. ball bearings – шариковые подшипники

friction bearings– подшипники скольжения

roller bearings – роликовые подшипники

5. a cage – сепаратор (подшипника качения)

6. a gear train – зубчатая передача, блок шестерен

7. gearing – зубчатая передача, механизм привода

8. meshing teeth – постоянное зацепление

9. a spur gear – целиндрическое прямозубое колесо, зубчатая шестерня

10. an idler gear – паразитная (промежуточная) шестерня

11. a driving gear – ведущая шестерня

12. a bevel gear – коническое зубчатое колесо

13. a helical gear – геликондальное (косозубое) зубчатое колесо

14. rather than - а не…, скорее чем …

15. a worm gear – червячная передача

VIII. Письменно ответьте на следующие вопросы к тексту:

1. What is a bearing?

2. What types of bearings are used in engineering?

3. What is a gear?

4. What forms of gearing are distinguished in mechanics?