Question

1. His plan is (keep) the affair secret.

2. It is dangerous (lean) out of the window.

3. You had better (say) nothing.

4. (Open) the window!

5. He made me (move) my car.

6. You are too young (understand).

7. No (smoke).

Answer 1

1. His plan is (keep) to keep the affair secret.

2. It is dangerous (lean) to lean out of the window.

3. You had better (say) say nothing.

4. (Open) open the window!

5. He made me (move) move my car.

6. You are too young (understand)to understand.

7. No (smoke)smoking.

Answer 2

1. to keep 

2.to lean

3. say

4. Open

5. move

6. to understand

 7. smoking