Correct the sentences in which the tenses are misused.
1. They completed all the preparations by five o’clock.
2. Please, tell me where you were going to yesterday at 3 o’clock..
3. I had written to you several days ago. I wanted to know more about the entrance exams.
4. She had returned from Chicago yesterday.
5. When she came back she found out that somebody had broken the front door.
6. What did you do at this time yesterday? I was skating .
7. Have you been waiting for me for a long time? Yes, I have waited for you since 2 o’clock.
8. I returned home, shook the water off my raincoat and hang it up.
9. Everything had been ready by 2. So when I came the hostess was having a rest before the guests arrived.
10. He found the place even more beautiful than he expected.
11. We could not start the experiment before we had obtained the necessary data..
12. The use of metals had marked one of the greatest stages in the evolution of man.
13. At the same time they were discussing the results of the experiment.
14. The treatment of steel is now an elaborate science.
15. The use of vacuum methods in metallurgy considerably increased since the mid-fifties.