45. - How are you feeling here?

　 - It's quite hot. I don't know ______ to go or stay.

　 A. how 　　　　　　　　　 B. when 　　　　　　　　　　　 C. whether 　　　　　 D. where

44. - He is slow in studying. I wonder how he could get good results in the exam.

　 - No wonder he is always ______.

　 A. lively 　　　　　　　　 B. hard-working 　　　　　 C. kind-hearted 　　 D. helpful

43. - Do I have to come back tomorrow?

　 - Yes, you______.

　 A. can 　　　　　　　　　 B. may 　　　　　　　　　　　 C. must 　　　　　　　 D. should

42. - How can I tell one tree from another?

　 - You can mostly tell them by the______ of their leaves.

　 A. shape 　　　　　　　　 B. size 　　　　　　　　　　　　 C. age 　　　　　　　　 D. color

41. - What's up?

　 - I can't stand the noise outside. It's nearly______ me mad.

　 A. keeping 　　　　　　 B. turning 　　　　　　　　　 C. causing 　　　　　 D. driving