27.Every time Ashtita tries to break a record, he reaches a point ______ he feels he cannot physically do any more.
A.where B.that C.when D.which
26.The boy talked his mother ________ buying him a home computer.
A.of B.over C.to D.into
25.When ______ about the secret of his success, Steven Spielberg said that he owes much of his success and happiness ________ his wife and children.
A.asking; to B.asked; in
C.asked; to D.asked; about
24.To enjoy the scenery, Sara would spend long hours on the train ______ travel by air.
A.as to B.other than C.instead of D.rather than
23.The audience ______ when they heard the humorous story.
A.burst into laughing B.burst out laughter
C.burst into laughter D.burst in laughing
22.- I’m sorry.That wasn’t of much help.
- Oh, _______ .As a matter of fact,it was most helpful.
A.sure it was B.it doesn’t matter
C.of course not D.thanks anyway
第一节 单项填空(共15小题,每小题1分,满分15分)
21.- What about ______ lecture you attended yesterday?
- To tell the truth, it was too boring.I can't stand ______ lecture like that.
A.a; the B.the; a C.the; 不填 D.the; the
15.有两排座位,前排11个座位,后排12个座位,现安排2人就座,规定前排中间的3个座位不能坐,并且这2人不左右相邻,共有多少种不同排法?
解:∵前排中间3个座位不能坐,
∴实际可坐的位置前排8个,后排12个.
(1)两人一个前排,一个后排,方法数为C·C·A种;
(2)两人均在后排左右不相邻,共A-A·A=A种;
(3)两人均在前排,又分两类:
①两人一左一右,共C·C·A种;
②两人同左同右,有2(A-A·A)种.
综上可知,不同排法种数为
C·C·A+A+C·C·A+2(A-A·A)=346种.
14.已知平面α∥β,在α内有4个点,在β内有6个点.
(1)过这10个点中的3点作一平面,最多可作多少个不同平面?
(2)以这些点为顶点,最多可作多少个三棱锥?
(3)上述三棱锥中最多可以有多少个不同的体积?
解:(1)所作出的平面有三类:①α内1点,β内2点确定的平面,有C·C个;②α内2点,β内1点确定的平面,有C·C个;③α,β本身.
∴所作的平面最多有C·C+C·C+2=98(个).
(2)所作的三棱锥有三类:①α内1点,β内3点确定的三棱锥,有C·C个;②α内2点,β内2点确定的三棱锥,有C·C个;③α内3点,β内1点确定的三棱锥,有C·C个.
∴最多可作出的三棱锥有:
C·C+C·C+C·C=194(个)
(3)∵当等底面积、等高的情况下三棱锥的体积相等.
且平面α∥β,∴体积不相同的三棱锥最多有
C+C+C·C=114(个)
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