31. He didn’t know the news _______ his parents told him about it.

　 A. when　　　 B. after　　 C. as soon as　　 D. until

30. A good friend always gives you a helping hand ______ you’re in trouble.

A. when　　　　 B. before　　 C. until　　 D. though

28. Mr Huang decided to buy that CD player ______ it was expensive.

　 A. even though　 B. so that 　C. because　　 D. as if

27. He can’t decide which to choose ______ there is no difference between them.

　 A. but　　 　　　 B. so　　　 C. because

26. Ted tried his best, ______ he caught up with the others at last.

　 A. but　　　 B. or　　 C. and　　　 D. because

25. Maths is not easy to learn, ______ we must work herder.

　 A. but　　　 B. or　　 C. so　　 C. and

24.-Your picture is wonderful!

　 -I worked for 8 hours ______ I finished it.

　 A. when　　 B. before　　 C. while　 D. after

23. The question is ______ he won’t listen to anyone.

　 A. that　　　 B. whether　　 C. if　　 D. when

22.-Would you please give this MP3 to Mary ?

　 -Sure. I’ll give it to her ______ she come back..

　 A. before　　 B. as soon as　　 C. till

21. What should I do ______ I want to be thinner ?

　 A. though　　 B. unless　　 C. but　　 D. if