Выберите правильный вариант ответа.
1. She has taught English ... five years.

a) by
b) at
c) for

2. We have been living here ... March.

a) for
b) since
c) about

3. I'll become a senior lieutenant ... next month.

a) in
b) -
c) for

4. I won't be out very long. I'll be back ... ten minutes.

a) since
b) at
c) in