Fill in the blanks with the right form of the verb in brackets ('If' / 'unless' usage):
1. a. The rain may stop. Then the match will be resumed.
b. If the rain _________ (stop), the match ____________ (resume).
2. a. He should work hard. He can get a good result.
b. If he _______ (work) hard, he ________ (get) a good result.
3. a. Run fast to catch the bus.
b. If you ______ (run) fast, you may catch the bus.
4. a. I don't know her name. I cannot call her.
b. If I ________ (know) her name, I __________ (call) her.
5. a. I am not a bird. I cannot fly.
b.If I _____ (be) a bird, I _________ (fly).
Answers: 1.(stops, will be resumed) 2.(works, can get) 3.(run)
4.(knew, could call) 5.(were, could fly)
6. a. He did not come in time. He missed the lecture.
b. If he __________ (come) in time, he might not _______ (miss) the lecture.
7. a. He was angry. He did not answer my questions.
b. If he ________ (be) angry, he ____________(answer) my questions.
8. a. He didn't have enough money. He could not buy the house.
b. If he _______ (have) enough money, he ___________ (buy) the house.
9. a. He couldn't run. His ankle was swollen.
b. If his ankle __________ (be, swell), he _____ (run).
10. a.We can't appreciate light if haven't known darkness.
b.Unless we have __________ (know) darkness, we can't appreciate light.
Answers: 6.(had come, have missed)
7.(had not been, would / could / might have answered)
8.(had had, could have bought)
9.(had not been swollen, could have run)
11. a. We cannot kill a tree without digging out its roots.
b. Unless we _________ (dig) out the roots, we cannot kill a tree.
12. a. She should know the truth. Then, she can forgive you.
b. Unless she __________ (know) the truth, she can not forgive you.
Answers: 11. (dig) 12. (knows)