一台单缸四冲程柴油机，飞轮转速为3600转/分，该柴油机活塞1s对外做功____

一个截面是直角三角形的木块放在水平地面上，在斜面上放一个光滑球，球的一侧靠在竖直墙上，木块处于静止，如图所示．若在光滑球的最高点再施加一个竖直向下的力F，木块仍处于静止，则木块对地面的压力N和摩擦力f的变化情况是 （　　）

A．N不变

B．N增大

C．f不变

D．f增大

完成句子

阅读下列各小题,根据每句后的汉语提示,用句末括号内的英语单词完成句子.

1. How time flies! Two years has been ________________.(realize)

时间过得真快啊!不知不觉中两年已经过去了.

2. ____________________ is that they are creative and strongwilled.(what; common)

他们的共同之处是他们都富有创造力并且意志坚定.

3. ____________________ the Earth Day program on TV that we knew much about global warming.

    (until)

直到我们在电视上看了《地球日》这个节目,我们才对全球气候变暖更加了解.

4. Students should be brought up to know that love, happiness and success are ____________________.(what)

学生从小就应该知道,爱、幸福和成功是金钱买不到的.

5. ____________________that very few people make a complete shopping list before going to the

    supermarket, especially on Christmas Eve. (find)

已经发现很少有人在购物之前会写下完整的购物单,尤其是在圣诞前夜.

6. Many people ____________________when others talk to them with their mouthful. (hate)

许多人讨厌别人在满嘴是食物的时候讲话.

7. People always ____________________that those who get good grade in the entrance examination

    will prove to be the most successful.(grant)

人们总是理所当然地认为在高考中取得高分的人会是最成功的.

8. The boy ____________________his experience that he fainted when the doctor put a needle in his

    arm and took out some blood. (ashamed)

这个男孩对于在医生把针扎进他的手臂抽血的时候晕倒这个经历感到羞愧.

9. When he was at college, he developed an interest in music,____________________ a lot in his later

     life.(benefit)

当他上大学的时候,他对音乐产生了兴趣,在以后的日子里他从中获益匪浅.

10. ____________________,he had no difficulty covering 20 kilometers in four hours.(accustom)

因为习惯于长距离步行,他毫不费力地在四个小时里走了20公里.

病理学区别天疱疮和类天疱疮时的主要依据是（）

A.是否出现蝶形红斑

B.疱损与上皮基底膜的关系

C.发病的急缓

D.疱损愈合后留下瘢痕

E.是否出现白色角化条纹

压水罐安装时其四周要设检修通道，其宽度不宜小于（）m，消防气压给水设备顶部至楼板或梁底的距离不宜小于（）m。

A.0.6，0.7

B.0.6，0.8

C.0.7，0.6

D.0.7，0.8

在值班期间，值班人员需要移开或越过遮拦时（）。

A、必须先停电

B、填写工作票

C、必须有监护人在场