Question

Put the Verbs in the brackets in the correct forms 1. For many years scientists (to study) the nucleus before they found that it is possible to split it. 2. Many power stations (to use) atomic energy for a long time before I knew it. 3. All this period scientists and engineers (to develop) rocket technology and electronics in close cooperation. 4. We widely (to use) electronic devices in industry for many years. 5. We know that our astronomers (to observe) the moon for a long time. 6. My friend (to make) these experiments to compare the weight of elements since the first of September 7. The question about the new experiment on this subject (to discuss) for some time before we came to a definite conclusion. 8. The fact that atom has a nucleus in its center, which is positively charged, (to discuss) by Ernest Rutherford in 1911. 9. This problem (to solve) in the near future. 10. The phenomenon of radioactivity (to use) widely in industry, medicine and agriculture 11. He found that this effect (to cause) by some unknown subatomic particles. 12. The weights of these particles (to calculate) with the help of electronic computer. 13. U-238 (to convert) into plutonium and then (to use) to generate atomic power. 14. These substances (to refer to) usually as hydrogen isotopes 15. One of the isotopes of hydrogen (to call) deuterium. 16. He (to puzzle) by these unexpected results. 17. It (to show) that these substances differed greatly in their chemical properties. 18. It (to expect) that the results of our research (to apply) in chemical industry.

Answer 1

1) studied

2) were using

3) developed

4) used

5) were observing

6) made

7) was discussing

8) was discuss

9) will solve

10) is using

11) caused

12) calculating

13) was converted, used

14) are referring

15) calls

16) was puzzled

17) shows

18) expects, will apply

Answer 2

1. For many years, scientists had been studying the nucleus before they found that it is possible to split it.
2. Many power stations had been using atomic energy for a long time before I knew it.
3. All this period, scientists and engineers have been developing rocket technology and electronics in close cooperation.
4. We have been using electronic devices in industry for many years.
5. We know that our astronomers have been observing the moon for a long time.
6. My friend has been making these experiments to compare the weight of elements since the first of September.
7. The question about the new experiment on this subject had been discussed for some time before we came to a definite conclusion.
8. The fact that the atom has a nucleus in its center, which is positively charged, was discussed by Ernest Rutherford in 1911.
9. This problem will be solved in the near future.
10. The phenomenon of radioactivity has been used widely in industry, medicine, and agriculture.
11. He found that this effect was caused by some unknown subatomic particles.
12. The weights of these particles were calculated with the help of an electronic computer.
13. U-238 is converted into plutonium and then is used to generate atomic power.
14. These substances are referred to usually as hydrogen isotopes.
15. One of the isotopes of hydrogen is called deuterium.
16. He was puzzled by these unexpected results.
17. It was shown that these substances differed greatly in their chemical properties.
18. It is expected that the results of our research will be applied in the chemical industry.