Choose one right answer. 3. We ... much scientific literature lately. a) have b) have read c) read 4. The Celsius scale ... in most scientific experiments. a) is b)used c) is used 5. Tsiolkovsky's works and his ideas ... the basis of the modern theory of jet propulsion. a)had b) have c) have become 6.The elements predicted by Mendeleyev ... later by scientists from different countries. a) discovered b)were discovered c) was discovered 7. Unless tested the machine ... not be put into operation. a) must b) may c) can 8. Steam usually ... in a boiler by a fire. a) are generated b) is generated c) generated 9. The problem of scientific classification ... from several viewpoints. a) can approached b) be approached c) can be approached 10. Automatized information processing radically ... the method devised. a) modified b) is modified c) can be modified