24. Since no one had any more matches, there was nothing with which to ________ the fireworks.

A. set out　　　 B. set about　　 C. set off　　　 D. set up

23.The flight attendant welcomed us __________ the plane.

A.abroad　　　 B.. aboard　　　 C. board　　　 D. broad

22. ______, a man who expresses himself effectively is sure to succeed more rapidly than a man whose command of English is poor.

A.Other things being equal　　　　 　　B. Other things be equal

C. To be equal to other things　　　　　 D. Other things to be equal

第一节：单项填空(共15小题；每小题1分，满分15分)从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。

21. What _______ wonderful world it would be if all countries in the world could live in ______

peace with each other.

A. a; the　　 B. the; a　　 C. a; 不填　　　 D the；不填

第一节：

1. What will they do tonight?　

A. Play music　 B. Dance　 C. Listen to music.

2. Where is the woman going first?

A. To the cinema　 B. To the shop　　 C. To the post office

3. What is wanted in the ad ?

A. Waiter　　 B. Waitress　　 C.Cook

4. What are the two speakers talking about?

A. A fine boat　　 B. Their friend, Tom　　 C. The weather

5. What will the man do this Saturday?

A.He’s going to the woman’s home.　 B. He’s going to meet the woman’s family instead of her.　　　 C.He’s going to have dinner with the woman’s family in a restaurant.　

22.(本题满分14分)已知上是减函数，且.

(Ⅰ)求的值，并求出和的取值范围;

(Ⅱ)求证：；

(Ⅲ)求的取值范围，并写出当取最小值时的的解析式.

21. (本小题满分12分)已知点集, 其中

为向量, 点列在点集中, 为的轨迹与轴的交点, 已知数列为等差数列, 且公差为1,

(1)求数列,的通项公式;

(2) 求的最小值;

(3) 设, 求的值.

20. (本小题满分12分)如图：PA⊥平面ABCD，ABCD是矩形，PA=AB=1，PD与平面ABCD所成角是30°，点F是PB的中点，点E在边BC上移动.

　 (Ⅰ)点E为BC的中点时，试判断EF与平面PAC的位置关系,并说明理由；

　 (Ⅱ)证明：无论点E在边BC的何处，都有PE⊥AF；

　 (Ⅲ)当BE等于何值时，二面角P-DE-A的大小为45°.