单选题设f(x)=x(x+1)(x+2)，则f''(x)=( ) A．6 B．2 C．1 D．0

单选题一水池有两个进水管A，B，一个出水管C．若单开A管，12h可灌满水池，单开B管，9h可灌满水池，单开C管，满池的水8h可放完．现A，B，C三管齐开，则水池灌满水需要______．

单选题球的内接正方体的棱长为，则此球的表面积是______A．2πB．C．D．6πE．8π

单选题设k为常数，则极限

单选题甲、乙、丙三人射击，他们的命中率分别为．现在三人同时射击目标，则目标被击中的概率为______．A．B．C．D．E．

单选题用电锯把一根长2m的钢材锯成5段，需要24min，照这样计算，如果把同样长的钢材锯成7段，需要用( )min．

单选题[2009年10月]一艘小轮船上午8：00起航逆流而上(设船速和水流速度一定)，中途船上一块木板落入水中，直到8：50船员才发现这块重要的木板丢失，立即调转船头去追，最终于9：20追上木板。由上述数据可以算出木板落水的时间是( )。

单选题设f(x)为可导函数，则[∫f(x)dx]'等于( )。 A．f(x) B．f(x)+C C．f'(x) D．f'(x)+C

单选题7个人排成一排，甲不在排头且乙不在排尾的排法共有______种．

单选题如图所示，有一圆柱，高h=12厘米，底面半径r=3厘米，在圆柱下底面的点A处有一只蚂蚁，沿圆柱表面爬行到同一纵切面的斜上方的B点，则蚂蚁沿侧面爬行时最短路程是______．(π≈3)

单选题某班第一小组共有12位同学，现在要调换座位，使其中3个人都不坐自己原来的座位，其他9个人的座位不变，共有( )种不同的调换方法．

单选题Is athletic expertise attained or innate? Those who have suffered the tongue-lashing of a cruel games master at school might be forgiven for doubting the idea that anyone and everyone is capable of great sporting achievement, if only they would put enough effort into it. Practice may make perfect, but not all are built in ways that make it worth bothering in the first place. The latest evidence of this truth has been gathered by Sabrina Lee of Simon Fraser University in Vancouver and Stephen Piazza at Pennsylvania State University. They have looked at the physical structure of short-distance runners and found that their feet are built differently from those ofcouch potatoes. Dr. Lee and Dr. Piazza already knew that short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs than more sedentary folk can muster. They suspected, though, that they would find differences in the bone structure as well. And they did. They looked at seven university sprinters who specialize in the 100-metre dash and five 200-metre specialists, and compared them with 12 non-athletic university students of the same height. In particular, they looked at the sizes of bones of the toes and heel. They also used ultrasonic scanning to measure the sliding motion of the Achilles tendons of their volunteers as their feet moved up and down. This allowed them to study the length of the lever created by the tendon as it pulls on the back of the heel to make the foot flex and push off the ground. Dr. Lee and Dr. Piazza found that the toes of their short-distance runners averaged 8.2cm in length, while those of common people averaged 7.3cm. The length of the lever of bone that the Achilles tendon pulls on also differed, being a quarter shorter in short-distance runners. These findings suggest short-distance runners get better contact with the ground by having longer toes. That makes sense, as it creates a firmer platform to push against. In a short-distance running race, acceleration off the block is everything. Cheetahs, the champion of short-distance runners of the animal kingdom, have non-flexible claws that give a similar advantage. It is possible—just—that the differences in physical structure are the result of long and rigorous training. But it is unlikely. Far more probable is that the old saying of coaches, that great short-distance runners are born not made, is true. Everyone else, games masters included, should just get used to the idea.