48．It seems oil　　　　 from this pipe for some time, we’ll have to take the machine apart to put

　　　　　　　 it right.

A．had leaked B．is leaking　 C．leaked　　　 D．has been leaking

47．His letter was especially welcome as I ____ from him for long.

A．haven’t heard B．would not heard　　　 C．hadn’t heard 　 D．didn’t heard

46．-May I speak to your manager Mr.Williams at five o’clock tonight?

-I’m sorry. Mr. Williams ________ to a conference long before then.

A．will have gone　 B．had gone　 C．would have gone　　 D．has gone

45．-Why were you not at the concert?

　　　 -I________ a close game between two European football teams.

A．watched　　　　 B．had watched　　 C．was watching　 　　　 D．have been watching

44．We　_______　on　it　for　several　hours　but　we　have　not　yet　reached　any　conclusion.

A．work B．are　working　　　 C．have　been　working　D．have　been　worked

43．I ____ to go for a walk, but someone called and I couldn’t get away.

A．was planning　　 B．planned 　 C．had planned　　　 D．would plan

42．Salley________Beijing for Shanghai and________there ever since. You can go and pay her a

　　　 visit on your way to Hangzhou.

　　　 A．has left; worked　　　 B．left; worked　　　 　　　

　　　 C．has left; had worked 　　　 D．left; has worked

41．-Why do you look so worried?

-Fred left the company half an hour ago. His work _______ unfinished since.

A．left　　 B．was left　　 C．has left　　 D．has been left

40. A new technique ____ out, the yields (收成) increased by 20% .

A. having working　　　　 B. having been working　

C. has worked　　　　　　 D. had been worked

39. ---What do you think of my suggestion?

--- Sorry. What's that? I ____ about something else.

A. thought B. am thinking　 C. was thinking D. had thought