Exercise 9. Find the mistakes and correct them.

1. Sydney Harbour Bridge was building in 1932.
2. While they were carrying out tests in the laboratories. researchers were analysing past results.
3. The first real road builders in Britain was the Romans.
4. The Romans built roads of layers of broken stones of various sizes and were covering them with flat stones.
5. The system didn't working because the loudspeaker had been wrongly connected.
6. Before factories were told to stop polluting the environment, waste was being dumped in rivers and in the sea.
7. Louis Pasteur was discovering the action of germs while he was studying fermentation in wines.
8. The production process had already been shut down when the leak in the fuel tank was found.
9. Nuclear energy began to be used from the mid-1950s.
10. In the second half of the 20th century, the electronics industry transforming the way we work in factories.