20. I didn’t watch TV last night because I was busy. If………………………………………………………………………………………………………… 21. People don’t see the UFO, so they don’t call the National UFO Reporting Center. If………………………………………………………………………………………………………… 22. Thu can’t swim, so she doesn’t go swimming in Lam Son Swimming pool. If………………………………………………………………………………………………………… 23. His flight was delayed so he couldn’t be there on time. If………………………………………………………………………………………………………… 24. Thanks to Lisa’s report, I was able to finish the project. If………………………………………………………………………………………………………… 25. Without your help, I couldn’t overcome the problem. If………………………………………………………………………………………………………… 26. She didn’t stop her car because she didn’t see the signal. If………………………………………………………………………………………………………… 27. They do not understand you because you speak too fast. If………………………………………………………………………………………………………… 28. He doesn’t apply for the job because he doesn’t have enough qualifications. If………………………………………………………………………………………………………… 29. He never polishes his shoes, so he never looks smart. If………………………………………………………………………………………………………… 30. Go right now or you will be late for the train. If…………………………………………………………………………………………………………

20. If I wasn't busy last night, I would watched TV.

21. If people saw the UFO, they would called the National UFO Reporting Center.

22. If Thu could swim, she would went swimming in Lam Son Swimming pool.

23. If his flight wasn't delayed, he could been there on time.

24. If Lisa didn't report, I wasn't able to finished the project.

25. If you didn't help, I couldn't overcome the problem.

26. If she saw the signal, she would stopped her car.

27. If you didn't speak too fast, they could understood you.

28. If He had enough qualifications, he could apply for the job.

29. If he polished his shoses, he could looked smart.

30. If you didn't go right now, you would late for the train.

20. If I were not busy last night, I would have watched TV.

21. If people saw the UFO, they would call the National UFO Reporting Center.

22. If Thu could swim, she would go swimming in Lam Son Swimming pool.

23. If he had been there on time, his flight wouldn't have been delayed.

24. If Lisa had not reported me, I would not have been able to finish the project.

25. If you had not helped me, I would not have overcome this problem.

26. If she had not seen the signal, she would have stopped her car.

27. If you did not speak too fast, they would understand you.

28. If he had enough qualifications, he would apply for the job.

29. If he polished his shoes, he would look smart.

30. If you do not go right now, you will be late for the train.