2.12. Reread the text and rewrite the following according to the model, replacing the words in italics with an expression from the text which has a similar meaning.
Model: An increase in length of 0.003mm was found in a bar subjected to a force of 1.5kN.
A force of 1.5kN will lengthen a bar by 0.003mm.
A tensile force of 2kN applied to a bar of steel will cause its size and shape to change.
The shaft has a uniform c.s.a.
If a bar of iron undergoes a force of 2kN, it bends.
Copper is a material which has the property of elasticity.
The body will not then return to its original dimensions.
A body which undergoes a tensile force will lengthen.
When compressive forces go beyond the elastic limit, permanent distortion results.
Changing from active into passive The object of the active verb becomes the subject in the passive sentence. The active verb changes into a passive form and the subject of the active verb becomes the agent, which is either introduced with “by” or is omitted when it is not important. Bell invented the telephone. → The telephone was invented by Bell. They used new materials. → New materials were used. Who developed this method? → Who was this method developed by? |
2.13. Find the subject and the object in these sentences (see the model above) then rewrite them in the passive.
We use the steel grades (марки стали) in shipbuilding.
Two laboratories will study this problem.
The Academy of Sciences organized the conference.
We rarely find pure metals in nature.
Lavoisier gave the name of hydrogen to this element.
They equipped our laboratory with new computers.
Ancient people have employed bronze since the prehistoric times.
Who discovered this element?
Two or more elements make up a compound.
2.14. Translate the following proverbs. Pay attention to the use and meaning of Participle II.
1. Well begun is half done.
2. A bored guest is a boring guest.
3. What is done cannot be undone.
4. Once said, a word cannot be unsaid.
5. What can't be cured must be endured.
6. First come first served.
7. Easier said than done.
8. Ask no questions and you will be told no lies.
2.15. Examine the diagram and complete the following text with the words from the word list.
becomes, even, fractures, its, length, tension, original, possible, regain, stretches, very, used
This machine is (1) ……. for testing tensile strength. The machine slowly (2) ……. a metal bar under tension.
A mild steel bar is not (3) ……. elastic, but it stretches under low tension. Remove the (4) ……. and it regains its (5) ……. length. Increase the tension and it stretches to a greater (6) …….. .The middle of the bar (7) ……. thinner. Under medium tension, the bar does not retain (8) ……. elasticity. Remove the tension now and it does not (9) ……. its original length. Under high tension, the bar becomes (10) ……. thinner. Finally, it (11) ……. in the middle. It is (12) ……. to measure exactly the breaking point of the bar.
Notes
tensile strength – предел прочности на растяжение
breaking point – разрушающее напряжение