23. We would save thousands of lives if ________________. A. we found the remedy for the flu B. we had not found the remedy for the flu C. we find the remedy for the flu D. we’ll find the remedy for the flu 24. I won’t accept unless ____________. A. Tom to apologize B. Tom is apologizing C. Tom apologizes D. When Tom apologizes 25. I’ll help you if __________________. A. you told me the truth B. you tell me the truth C. you will tell me the truth D. you have told me the truth 26. I wouldn’t have got wet ____. A. if I had an umbrella with me. B. if I had had an umbrella with me C. Unless I had had an umbrella with me D. in case I had an umbrella with me 27. _____________ , he would not have had the accident yesterday. A. If Peter driven more carefully B. If had Peter driven more carefully C. Had Peter driven more carefully D. Unless Peter had driven more carefully 28. I didn’t listen to him and I didn’t succeed. A. If I listened to him, I would have succeed. B. If I had listened to him, I’d have succeeded. C. If I had listened to him, I would succeed. D. If I listened to him, I would succeed. 29. If he doesn’t apologize, I will never invite him here again. A. Unless he apologizes, then I will never invite him here again. B. Unless he apologizes, or I will never invite him here again. C. Unless he doesn’t apologize, I will never invite him here again. D. Unless he apologizes, I will never invite him here again. 30. I have to work tomorrow morning, so I can’t meet you. A. If I don’t have to work tomorrow morning, I can meet you. B. If I didn’t have to work tomorrow morning, I would meet you. C. I could meet you if I don’t have to work tomorrow morning. D. I can meet you if I didn’t have to work tomorrow morning. 31. Do your homework first and I’ll let you play the computer games. A. I won’t allow you to do homework when you play the computer games. B. Let’s play the computer games without doing your homework. C. You are allowed to play the computer games without doing your homework. D. Unless you do homework first, I won’t let you play the computer games. 32. I don’t have enough money with me now; otherwise I would buy that coat