性学囊括了与性相关的广博知识领域。它的三大支柱是（）。A.性医学 B.性教育学 C.

Beijing leading schools say “No” to students’ mobile phones.

Three reasons make some leading schools in Beijing discourage middle school students from bringing mobile phones to campus.

First, it is dangerous for children to bring valuable mobile phones along to school for it is possible for them to be lost during physical exercise and other activities and may cause unnecessary trouble to teachers.

Second, mobile phones are bad for students’ studies. Many teachers complain that some students have phone calls in class, disturbing themselves and others.

Third, mobile phones serve as a hotbed for students’ vanity（虚荣）. A new Grade One senior high school student in a leading school asked his parents to buy a 4000-yuan colored-screen mobile phone, which turned out to be his fifth one ever since he entered the middle school.

Most headmasters and teachers in leading schools of Beijing thought that IC telephones on campus have made it very easy for students to get in touch with others, so middle school students should not bring mobile phones to school at present.

1. According to the passage, without mobile phones, how can the students get in touch with others?

A. By writing letters to each other.                       B. By sending e-mails.

C. By using IC telephones.                          D. By no means.

2. Which is NOT the reason that makes the schools say “No” to students’ mobile phones?

A. It is not safe for children to bring mobile phones to school.

B. It may give students a feeling of vanity.

C. It is bad for students’ studies.

D. Most headmasters and teachers don’t want students to bring mobile phones to campus.

3. Why did the new Grade One student ask to buy him the fifth mobile phone since he entered the school?

A. His family had a lot of money.

B. He wanted to show that his family was very rich.

C. His parents loved him too much.

D. The first four mobile phones were all lost.

4. What is the writer’s attitude towards students’ bringing cell phones to school?

A. negative.         B. acceptable.        C. not mentioned.     D. positive. 

综采工作面当采高超过（）或片帮严重时，液压支架必须有护帮板，防止片帮伤人。

A.2.0m

B.2.5m

C.3.0m

D.4m

陈某与王某打架斗殴，乡派出所对陈某作出行政拘留的处罚，对王某作出罚款100元的处罚，陈某不服，申请行政复议。下列哪一选项说法是正确的（）

A.乡派出所对陈某做出拘留决定前，应告知陈某有申请听证的权利

B.派出所可以当场做出对王某的罚款决定，还可当场收缴

C.陈某申请复议，复议机关为县公安局

D.若王某也不服，可向县公安局申请复议

历节病的发病是由于肝肾气血不足，复感风寒湿邪所致。

为了保证在同一车站、同一时间内只准许选出一条进路，则四个方向继电器相互之间存在“互切”关系。