“民以食为天”，我国是世界上最早种植水稻的国家。你知道我国哪个地方的先民最早吃到

李强从甲地去乙地，去时先骑自行车，途中又换乘汽车，3小时到达乙地；回来时全乘汽车，1+4/5小时就到达乙地．单乘汽车比既骑自行车又乘骑车少用的时间相当于去时骑自行车时间的3/5．那么李强从甲地到乙地全部骑车需要多少小时？

阅读理解。

     Tom was one of the brightest boys in the year, with supportive parents. But when he was 15 he suddenly

stopped trying. He left school at 16 with only two scores for secondary school subjects. One of the reasons

that made it cool for him not to care was the power of his peer (同龄人) group.

     The lack of right male (男性的) role models in many of their lives - at home and particularly in the school

environment (环境)-means that their peers are the only people they have to judge themselves against.

     They don't see men succeeding in society so it doesn't occur to them that they could make something of

themselves. Without male teachers as a role model, the effect of peer actions and street culture (文化) is all-

powerful. Boys want to be part of a club. However, schools can provide the environment for change, and

provide the right role models for them. Teachers need to be trained to stop that but not in front of a child's

peers. You have to do it one to one, because that is when you see the real child.

     It's pointless sending a child home if he or she has done wrong. They see it as a welcome day off to watch

television or play computer games. Instead, schools should have a special unit where a child who has done

wrong goes for the day and gets advice about his problems - somewhere he can work away from his peers

and go home after the other children.

1. Why did Tom give up studying? 

A. He disliked his teachers.

B. His parents no longer supported him.

C. It's cool for boys of his age not to care about studies.

D. There were too many subjects in his secondary school.

2. What seems to have a bad effect on students like Tom?

A. Peer groups.

B. A special unit.

C. The student judges.

D. The home environment.

3. What should schools do to help the problem schoolboys?

A. Wait for their change patiently.

B. Train leaders of their peer groups.

C. Stop the development of street culture.

D. Give them lessons in a separate area.

4. A teacher's work is most effective with a schoolboy when he _____.

A. is with the boy alone

B. teaches the boy a lesson

C. sends the boy home as punishment

D. works together with another teacher

甲类功率放大器的集电极损耗（）

A、在输入信号最大时最大；

B、在输入信号为零时最大；

C、在输入信号为最大输入信号的50％时最大；

D、在输入信号为最大输入信号的70％时最大。

远程集中授权系统的业务管理员主要负责以下哪些管理工作（）。

A.机构信息维护

B.授权员信息维护

C.柜员的业务权限维护

D.各种业务运行参数的维护

下列哪个安全装置是用来防止运行小车超过最大或最小幅度的两个极限位置的安全装置？（）

A、起重量限制器

B、超高限制器

C、行程限制器

D、幅度限制器