7.Why does the woman refuse?

A.She has seen the film.

B.She is going away tonight.

C.She is not free.

听第7段材料，回答第8--9题。

6.Why does the man make a phone call the woman?

A.He wants to see a film with her.

B.He invites her to a dinner.

C.He tells her that he’ll visit her tonight.

5. What is the man going to do?

A.To open the door.

B.To open the window.

C.To carry the things for her.

第二节　 (共15小题；每小题 1.5 分，满分 22.5 分)

听第6段材料，回答第6--7题。

4.What is the probable relationship between the two speakers?

A.Boss and secretary

B.Teacher and students.

C.Libraian and book borrower.

3. Where does this conversation take place?

A.In a theater.

B.In a shop.

C.On a bus.

2. What are these two people going to do?

A.To have a meeting in the office.

B.To finish up the reports.

C.To have their lunch,

1.What time does the next plane to London leave?

A.At 10 o’clock.

B.At 11 o’clock.

C.At 12 o’clock.

21．(本小题满分12分)

已知数列的前n项和满足：(a为常数，且)。

　　 (I)求的通项公式；

　 (II)设，若数列为等比数列，求a的值；

　 (III)在满足条件(II)情形下，设，数列的前n项和为

　　　　 求证：

20．(本小题满分12分)

已知函数是定义在R上的奇函数。

　 (I)求a的值；

　 (II)当时，恒成立，求实数t的取值范围。

19．(本小题满分13分)

在中，a，b，c分别是角A，B，C的对边，且

　　 (I)求的值；

　 (II)若面积的最大值。