Question

Complete the sentences with the correct form of the present perfect or past simple. 1) Success of the Yablochkov candle in 1878 ________(exceed) all expectations – mass media all around the world ____(write) about the outstanding invention of a Russian scientist. 2) Electricity ______(be) a subject of scientific interest since at least the seventeenth century. 3) In the 19th century the subject of electrical engineering with tools of modern research techniques, __________(start) to intensify. 4) Electricity is used with telecommunications, and indeed the electrical telegraph, demonstrated in 1837 by Cooke and Wheatstone _____(be) one of its earliest applications. 6) Electricity is the best source of energy. While there are other sources of energy none of them __________(reach) the stage where they can be used to provide the power to help modern life go. 6) The processes used to produce electricity using the sun’s energy historically ________(be) more expensive than using conventional fossil fuels. 7) In 2015, less than 1% of the nation’s electricity __________(supply) by solar power. 8) In 1827 Georg Simon Ohm _________ (quantify) the relation between electrical current and potential difference between conductors – leading to Ohm’s law.

Answer 1

1 exceeded, wrote
2 has been
3 started
4 was
6 has reached
6 was
7 was supplied
8 quantified

Answer 2

1) The success of the Yablochkov candle in 1878 exceeded all expectations – mass media all around the world wrote about the outstanding invention of a Russian scientist. 2) Electricity has been a subject of scientific interest since at least the seventeenth century. 3) In the 19th century, the subject of electrical engineering, with tools of modern research techniques, started to intensify. 4) Electricity is used with telecommunications, and indeed, the electrical telegraph, demonstrated in 1837 by Cooke and Wheatstone, was one of its earliest applications. 5) Electricity is the best source of energy. While there are other sources of energy, none of them have reached the stage where they can be used to provide the power to help modern life go. 6) The processes used to produce electricity using the sun's energy historically have been more expensive than using conventional fossil fuels. 7) In 2015, less than 1% of the nation's electricity was supplied by solar power. 8) In 1827, Georg Simon Ohm quantified the relation between electrical current and potential difference between conductors – leading to Ohm's law.