1) You will be much safer if you (to drive) more carefully.

2) If the girls (not to play) with us we will leave the park.

3) She said she (to be) unhappy if he didn't join her the next day.

4) All of us will be here if she (to need) us.

5) What they (to do) if they had been given a phone call at that hour?

6) If I (not to know) how to arrive there I will call the principle.

7) They would have visited you last week if they (to find) out that you were in hospital.

8) He (to be) happy if he didn't lose his keys.

9) If I (to see) him I would surely give him the books he needs for his project.

10) The girls will play outside today if it (not to rain).