人体经口感染霍乱弧菌后描述不正确的是（）。 A.正常情况下被胃酸杀灭 B.未被胃酸杀

一个质量m="2" kg的物体在水平拉力F的作用下，在光滑水平面上从静止开始做匀加速直线运动，经过时间t="6" s速度变为v="12" m/s。求：

（1）物体的加速度a的大小；

（2）水平拉力F的大小．

肝豆状核变性的常见证候类型有（）

A.土虚木亢

B.痰湿阻络

C.气滞血瘀

D.肝阳上亢

E.气血亏虚

痰蒙心神证的表现应除外哪项( )

A．意识模糊

B．举止失常

C．神情痴呆

D．惊悸失眠

E．喃喃自语

In a public-key cryptosystem, (71) encrypted with the public key can only be deciphered with the private key from the same (72) . Conversely, (71) encrypted with the private key can be decrypted only with the public key. Users can make their public keys (73) available or place them at a key distribution center or others to access. However, the private key must be (74) safe. In public-key systems there’s no (75) to find a safe channel for communicating a shared secret key.

A. more B. necessary C. need D. space

In the world today, all of the people need recreation (消遣). We cannot work all the time if we are going to keep healthy and enjoy life.

Everyone has his own way of relaxing. Perhaps the most popular form is to take part in sports. There are team sports, such as basketball and football; There are also individual (个人的) sports, such as swimming and running. Skating and mountain climbing are the most popular recreation for people who like to be outdoor.

Not everyone who enjoys sports likes to take part in them. Many people like watching them on TV or listening to them on the radio. So many people like some forms of indoor recreation, such as watching TV, singing and dancing.

It doesn’t matter whether we like indoor recreation or take part in outdoor sports. It is important for everyone to relax from time to time, and enjoy some forms of recreation.

56．Which is the most popular form of recreation?

A．Sports.                             B．Watching TV.          

C．Sleeping.                         D．Singing and dancing.

57．People want to take part in sports in order to ____.

A．keep healthy and enjoy life         B．make friends

C．find a good job                   D．make more money

58．Outdoor sports include ____.

A．watching TV                      B．singing and dancing

C．listening to the radio              D．skating and mountain climbing

59．The passage mainly tells us that ____.

A．basketball is a kind of team sport

B．everyone who enjoys sports should take part in them

C．different people have different ways of relaxing

D．indoor recreation is not as important as outdoor sports