24. , you should set aside some time every day for exercise if you want to keep fit.
A.Busy as you are B.As busy are you
C.Busy as are you D.As busy you are
23.The soldier fired to warn the man forward.
A.to go B.going C.go D.against going
22.He failed to set new record, but it was good attempt.
A.a; a B.the; the C.a; the D./; /
第一节:语法和词汇知识(共15小题;每小题1分,满分15分)
21.--- You must have had a good time at the party last night, didn’t you?
--- . Actually, it was a bit boring.
A.Oh, great B.I suppose so C.Not really D.That’s OK
22.(12分)已知函数,其中,为常数。
(1)当时,求函数的极值;
(2)当时,证明对任意的正整数,当≥2时,≤.
21.(12分)已知数列的前项和,(为正整数)
(1)令,求证:数列是等差数列,并求数列的通项公式;
(2)令,试比较与的大小,并予以证明。
20.(12分)某地建一座桥,两端的桥墩已建好,这两桥墩相距米,余下的工程只需建两端桥墩之间的桥面和桥墩,经测算,一个桥墩工程费用为256万元;距离为米的相邻两墩之间的桥面工程费用为万元,假设桥墩等距离分布,所有桥墩都视为点,且不考虑其它因素,记余下工程费用为万元。
(1)试写出关于的函数关系式;
(2)当640米,需新建多少个桥墩才能使最小。
19.(12分)设函数在处取得极值,且曲线在点处的切线垂直于线
(1)求的值;
(2)若函数,讨论的单调性。