4．　　 在平面直角坐标系xOy中，“方程表示焦点在x轴上的双曲线”的充要条件是k∈­­­­­­　 ▲　 ．

3．　　 若复数，则实数a的值为　 ▲　 ．

2．　　 ­­­­­­­­函数的值域为　 ▲　 ．

1．　　 已知集合A＝{x|－1＜x＜2}，集合B＝{x|1＜x＜3}，则A∩B＝­­　 ▲　 ．

50.-Don’t interrupt me while I’m explaining the problems to you.

-____　　 __.

　 A .All right，go ahead　 　　B. It’s my pleasure　　 C. Of course，with pleasure　　 D. Not at all

49.-Can I take a week’s holiday, Sir?

-_________; we are too busy at present.

　 A. Don’t worry　　　 　　　 B. Don’t mention it 　　 C.Forget it　　　 　　　 D. No problem

48.-Thank you very much for helping me out of trouble, Bob.

-____________.

A. With pleasure　 　 B.Don’t mention it 　　　 C. That’s right　 　　　　　 D. I hope so

47.-Would you mind if I opened the window ?

-__　　 ____. In fact, I was going to suggest you __　　 __ it.

A. Yes; not did 　　B.Not at all; do　　 　C. More or less; did　　 D. Of course; do

46.- Shall we go out for a drink tonight?　 -__　　 ____.

A.You are right　　　 B. It must be funny　　 C.That sounds great　 D. Have a nice time.　

45. - How are you getting on with your work ?　 -　　 　　.

A.Thank you　　　　　 B.Fine , thank you 　　C.Quite well ,thank you　 D.Why do you ask so ?