Ответ:

1. The house opposite our college is being pulled down, that's why we are using the back entrance at present.

2. You had an umbrella when you left the house, didn't you?

3. By the time we got to the cinema the film had begun.  

4. Is there anything I can do to help you?

5. Last summer we wanted a relaxing holiday, so we chose to stay on a small island.

6. Someone is calling you. Will you answer the phone?

7. To tell the truth I don't like that pair of trousers that I bought last month.

8. Whose house is it? - It's mine.

9. Today is less cold than yesterday. So, I'm wearing my shorts.

10. When I was in the country I liked to get up at sunrise.