25.We visited the school that lies in _________was a big factory more than twenty years ago.

　　 A. what　　　　　　 B. which　　　　　　 C. that　　　　　　　 D. where

24. Criticism and self-criticism is necessary　　　　 it helps us to correct our mistakes.

　 　A. so　　　　　　　 B. however　　　　　 C. therefore　　　　 D. in that

23.　 ______ that he has no qualifications in education management, the man plans to gain the necessary skills by taking a part-time course.

A. To concern　　　 B. To be concerned　 C. Concerning　　　　　 D. Concerned

22. 　I would like __________you to my birthday party, but I was busy and forget to call you.

A. to invite　 　　　　B. inviting　　 　　　C. to have invited　　 　　　D. having invited

第一节：单项填空(共15小题；每小题1分，满分15分)

21. ---What ___________disappointment to see Liu Xiang quit his game in ________29th Beijing Olympic Games!

　 ----But I still support him. After all he is in poor health.

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

22. (本题满分12分)已知数列中,, 点在直线上.

(Ⅰ)求数列的通项公式；

(Ⅱ)若函数,求函数最小值;

(Ⅲ)设,表示数列的前项和,试问:是否存在关于的整式,使得

对于一切不小于2的自然数恒成立?若存在,写出的

21. 已知函数，且.

(Ⅰ)求的值域；

(Ⅱ)指出函数的单调性(不需证明)，并求解关于实数的不等式；

(Ⅲ)定义在上的函数满足，且当时求方程在区间上的解的个数.

20. (本题满分12分)如图，梯形中，，，是的中点，将沿折起，使点折到点的位置，且二面角的大小为.

(Ⅰ)求证：；

(Ⅱ)求直线与平面所成角的正弦值.