1)Though simple electric and magnetic phenomena ………… since ancient times, most basic laws of electricity were discovered between 1784 and 1831. a) was known; b) have been known; c) have known
2) After the text about the advantages of electricity………… the students went on reading about the application and consumption of electricity.
a) had read; b) had been read; c) has been read
3) We………… the resistance in each case before we begin to carry out the experiment.
calculate; b) will have calculated; c) will calculate
4) During the autumn of 1831 M. Faraday established the scientific foundation from which our electrical age ………….
a) has developed; b) has been developed; c) developed
5) He assumed that for many years the only practical electric invention made by B. Franklin …………. the lightning-rod.
a) had been; b) has been; c) was
6) In 1825 Sturgeon …………. the first electromagnet, the device in which magnetism was generated by an electric current.
a) exhibited; b) was exhibited; c) had exhibited
7) They claimed that the battery was one of those devices that………… more than once.
a) has been invented; b) had invented; c) had been invented
8) Scientists believe that by the end of the 21-st century the whole mankind…………with the new kinds of energy.
a) will be provided; b) will have been provided; c) will have provided
9) Electricity has provided mankind with the most efficient source of energy. No other source of energy………… so widely used as electricity.
a) have been; b) was; c) has been
10) M. Faraday discovered electromagnetic induction which led to the development of the electric dynamo and motor. He ………… lots of experiments before he published the results.
a) has made; b) made; c) had made