50. - If you fall into trouble, please let me know.

A. I will think it over　　　　 .　　　 B. I will never fall into trouble

B. I will. Thank you very much　　　　 D. I am very happy to hear that

49.　 - May I use your dictionary, Mary?

A. No, go ahead　　　　 B. Yes, help yourself

C. Of course not　　　 　D. It doesn't matter

48.　 - I am sorry to tell you that you shouldn't smoke here.　 Please look at the sign.

-　 Oh. I am sorry. I　　　　 it.

A. don' t notice　　　 B. didn't notice　　　 C. will notice　 D. haven' t notice

46.　 - What is the main cause of the accident?

-　 Driving________.

A. carefully　　　 B. careful　　　　　 C. careless　　　　 D. carelessly

47-　　　　 when the light went out last night?

A. What were you doing　　　　　　 B. What have you done

C. What did you do　　　　　 D. How were you doing

45.　 What's wrong with the orange? It_______　 terrible.

A. is tasting　　　 B. is tasted　　　 C. tastes　　　　　 D. tasted

44.　 - Mom, I'm going out with my classmates tonight.

-　 OK.　 But you'd better________ back too late.

A. don't come　　　　　　 B. not to come　　　 C. not coming　　　 D. not come

43.　 - Hi, Betty.　 Shall we go swimming this Sunday?

-　 This Sunday? I am sorry.　 I have a lot of homework _______ this Sunday.

A. to do　　　　　　 B. done　　　　　　 C. do　　　　 D. to be done