English exercises on tenses

English exercises on tenses. Fill in the gaps with the right forms of the verbs in capital letters at the end of the sentences.
1. Our company (produce) these cars since 1978.
2. Our company (produce) the car which Pope John Paul II used during his visit to South America last year.
3. I (try) o solve this problem for the last two hours.
4. He (solve) these problems for three hours now but I am afraid he (not solve) even one yet.
5. What (you do) when she came in?
6. We (wait) for you for ages. Please, do not keep us waiting next time.
7. I (hope) you will not find it difficult to cooperate with us.
8. It started to rain when I (dig) the garden.
9. While I (dig) the garden my brother-in-law (mow) the lawn.
10. (anyone here see) a leather glove?