Choose the correct answer

1. Doctors _____ a cure to AIDS yet.

A. have found

B. found

C. haven't found

D. hasn't found

2. Do you mind _____ up?

A. wash

B. washing

C. washed

D. to wash.

3. He _____ to give up smoking since last week.

A. was trying

B. have tried

C. has tried

D. tried.