Choose a, b, c to complete the sentences.

1. this law of mechanics one should know the theory well.
a. explaining b. to explain c. having explained
2. the plastics in our laboratory will replace iron and its alloys.
a. to be produced b. was producing c. have been produced
3. when the article he uses no dictionary.
a. translates b. translating c. translated
4. physics is a science with phenomena of matter and energy.
a. deals b. dealing c. was dealing
5. the new instrument in our laboratory will be used in radio engineering research.
a. designed b. designing c. being designed
6. every atom contains small particles kinds of electricity.
a. carrying b. carried c. carry
7. by young engineers the solar installations was used for melting metals.
a. designed b. having been designed c. having designed
8. the power station in our region will run on local coal.
a. built b. being built c. was built
9. a current through a conductor, a magnetic field is set up.
a. flowing b. flows c. having flown
10. the engine, the operator started it.
a. is tested b. was testing c. having been tested
11. a sensitive receiver , the electric oscillations could be directly proportional to conductivity.
a. are built b. having built c. having been built
12. other factors constant, the current is known to be directly proportional to conductivity.
a. be b. being c. having been