EX1: Give the correct tense of the verbs:
1. If it costs too much, I (buy) …………will buy…………….a small one.
2.If you (drive) ……………had driven…………….more carefully, you wouldn’t have so many accidents.
3.What (happen) ………………would happen………………..if there (not be) weren't gravity?
4.If I (make) ……………marked…………..that mistake again, my teacher (get) ……would get………… angry with me.
5.If I spoke English, my job (be) …………would be……………..a lot easier.
6.If he (go) ………had gone………………to London yesterday, he (meet) …………would have met…………..his old friend.
7.Would you mind if you suddenly (win) ……won……half a million pounds?
8.I (lend) ……will lend……..them some money if they (ask) …… ask…….me.
9.If we (know) …………had known…………who he was, we (invite) ……… would have invited………him to speak at our meeting.
10.If they had invited us, naturally we (go) ………would have gone……….to the party.
11.If Don and I (have) …… had….enough money, we would buy a house.
12.Ice (turn) …………will turn………..to water if you (heat) ……… heat…………it.
13.I (speak) ……would have spoken………….to France if I (see) ……had seen……him yesterday.
14.If I (realize) …had realized……that the traffic lights were red. I (stop) ……would have stoped…….
15.They (not / let) …………won't let…………….you in if you come late.
16.If you (not / go) ………don't go……………away, I’ll send for a policeman.
17.If I (be) ……were….in your place, I (accept) ……would accept…….Mr Long’s officer.
18.If I (win) ………won...…………a big prize in a lottery, I’d give up my job.
19.If Tom (be) ………had been………..here yesterday, he (be) ………would have been…………able to advise us. 
20.I was busy. If I (have) ………had had…………free time, I (go) ………would have gone………to the cinema with you.
EX2: Rewrite the following sentences by using conditional sentences.
11. He can’t go out because he has to study for his exam.
=> If……………………he didn't have to study for his exam,he could go out…………………… ………..
12. She is lazy so she can’t pass the exam.
If…………………………she weren't lazy, she could pass the exam……………… ………………
13. He will pay me tonight; I will have enough money to buy a car.
=> If…………………………He doesn't pay me tonight, I won't have enough money to buy a car……………… ………………….
14. He smokes too much; that’s why he can’t get rid of his cough.
=> If…………………………he didn't smoke too much, he could get rid of his cough……………… …………………..
15. She is very shy, so she doesn’t enjoy the party.
=> If……………………………she weren't shy, she would enjoy the party…………… …………………..
16. I will get a work permit. I will stay for another month.
=> If…………………………I don't get a work permit,I won't stay for another month……………… …………………..
17. He doesn’t take any exercises. He is so unhealthy
=> If……………………………he took any exercises,he wouldn't be so unhealthy…………… …………………….
18. We can’t get the ticket because I don’t have the right change.
=> If………………………I had the right change,we could get the ticket………………… ……………………..
19. Study hard or you won’t pass the exam.
=> If……………………….you don't study hard, you won't pass the exam………………… ………………………..
20. Don’t be impatient or you will make mistakes.
=> If…………………you are impatient , you will make mistakes……………………… 
21. I didn’t eat lunch, I feel hungry now.
=> If I…………..………I ate lunch , I wouldn't feel hungry now……………………….
22. If you want my advice,I would’t buy it.
=>If I ………… ………….were you,I would't buy it……………………………
23. I only come if they invite me.
=> unless……………….am invited,I will come…………………………….
24. He didn’t revise all his lessons, he failed the exam.
=> If he………………………… had revised all his lessons, he wouldn't have failed the exam.……………… ……………..
25. The park is over there, only 5 minutes’ walk.
=> If you walk………………for 5 minutes, you will see the park.…………………………….
26. In case it rain, we’ll stay at home
=>If it …………………… rains, we'll stay at home……………………………..
27. Let me give you my advice. You should cut down on smoking right now.
=> If I ……………………………were you, I would cut down on smoking right now……………………………………………
28. They are poor, so they can’t help us. 
…………………If they weren't poor, they could help us. ………………………….
29. She is very shy; that’s why she doesn’t enjoy parties.
…………………She will enjoy parties if she isn't shy.………………………….
30. He is very unhealthy because he doesn’t take any exercise.
…………………If he takes more exercises, he will be healthy.………………………….