8．About 80 percent of the students in our school_____ been working on the program and about two-thirds of the work _____been finished．

　　　　 A．have; has 　 　　　　　 B．has; have,　 　 　　 C．have; have　　 　　 D．has; has

7．Some people feel easy and comfortable to be served by others but when they are asked to serve others ______, they are unwilling or even hate to do so．

　　　　 A．in turn　　 　　　　　　 B．in their turns　 　　　 C．in their turn　 　　 D．by their turn

6．A story goes ______ Elizabeth I of England liked nothing more than being surrounded by clever and qualified noblemen at court．

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

5．______what many people thought, the graduate came here not to ______ fame or money but the true value of life．

　　　　 A．On the contrary with; look for　　　　　　　　　　 B．To the contrary of; hunt for

　　　　 C．Opposite to; search　　　　　　　　　　　　　　　　　　　　 D．Contrary to; seek

4．Sarah hopes to become a friend of ______ shares her interests．

　　　　 A．anyone　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 B．whomever　　　　　　　

　　　　 C．whoever　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 D．no matter who

3．Once one’s desire ______ reason, trouble is sure to follow．

　　　　 A．overcomes　 　　　　 B．is overcome by　 　 C．gets rid of 　　　　　　 D．is rid of

2．The other day, my brother drove his car down the street at _____ I thought was a dangerous speed．

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

1．When I was talking to her about her table manners, she stared at me as if listening to me attentively but I could see her mind ______somewhere else．

　　　　 A．wondering　 　　　　 B．wandering　 　　　　　 C．walking　 　　　　　　　　 D．thinking of

19．(本小题10分)“雪花曲线”因其形状类似雪花而得名，它可以以下列方式产生，如图，有一列曲线，已知是边长为1的等边三角形，是对进行如下操作得到：将的每条边三等分，以每边中间部分的线段为边，向外作等边三角形，再将中间部分的线段去掉()．

　 (1)记曲线的边长和边数分别为和(),求和的表达式;

　 (2)记为曲线所围成图形的面积,写出与的递推关系式，并求．

18．(本小题10分)已知点是的重心，过点的直线与分别交于两点．

　 (1)用表示；

　 (2)若试问是否为定值，

证明你的结论．