电子产品中至少有三种分开的地线，其中继电器、电动机或者高电平的地线称为（）。A、信号

阅读下面短文，把A-D四个句子填入文中空缺处（1-4），使短文内容完整正确，然

后完成第5题。

    Have you ever complained why life is so tiring? Does the sky sometimes seem dark to

you? Are your studies sometimes not successful? 1_____ If you see the world with your

warm heart, you'll find that the whole world smiles to you.

    While in school, sometimes you are tired of your lessons, but have you ever noticed the

happy smile on your teacher's face when you did a good job?

    One day it is fine. Just before you want to go out, it suddenly starts to rain. 2_____ But

dear friends, why don't you sit down and listen to the free concert that the nature offers you?

And with the timely rain, crops in the fields will grow better and better and farmers will have

a good harvest.

    Although everyone wants to succeed in what he tries to do, sometimes failure (失败) can't

be avoided. 3_____ When we face failure, we must be confident of ourselves, draw a useful

lesson from it and try our best to finish what we have decided to do. 4_____ 

    Attitude decides everything. With an optimistic (乐观) attitude life is easy and pleasant. Let's

smile to whatever we meet and the whole world will smile to us.

A. I think failure is not terrible, and the terrible thing is that we are afraid of it

    and give up hope.

B. Well, friends, cheer up and smile all t he time.

C. Maybe you would feel very sad and start complaining about the weather.

D. As a popular saying goes, "Failure is the mother of success."

5. The best title of this passage is _____. [ ]

A. Smile and the World Smiles to you

B. Complaining about the life

C. Failure is the Mother of Success

D. It is Very Hard to Succeed.

某学校组织七、八年级的学生到离校15千米的植物园春游，两个年级的学生同时出发，八年级学生的速度是七年级学生速度的1.2倍，结果八年级学生比七年级学生早到半小时，求七年级学生的速度．

警察产生的政治条件是( )。

A．生产力的发展和私有制的产生
B．阶级矛盾和统治阶级内部矛盾的不可调和性
C．维护统治秩序与惩罚犯罪的客观需要
D．国家机器的形成

1993年长江中下游某些地区发生洪涝灾害，夏粮严重歉收。但是哪些庄稼没有被水冲毁的农户却从水灾中获益，为什么？

职业生活中的法律更多地体现为社会对一定职业活动的（）。

A.改革意识

B.他律要求

C.创新意识

D.自律意识