把两个相同的金属小球接触一下再分开一个很小的距离，发现两球相_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题不定项选择

把两个相同的金属小球接触一下再分开一个很小的距离，发现两球相互排斥，则这两个小球原来的带电情况可能是

①两球带等量异号电荷

②两球带等量同号电荷

③两球原来带不等量同号电荷

④两球原来带不等量异号电荷 [ ]

A．①②③④

B．①②③

C．②③④

D．①③④

答案

答案：C

改错题

短文改错。
     此题要求改正所给短文中的错误。对标有题号的每一行做出判断：
     如有错误（每行只有一个错误），则按下列情况改正：
     1. 该行多一个词：把多余的词用斜线(＼)划掉，在该行右边横线上写出该词，并也用
斜线划掉。
     2. 该行缺一个词：在缺词处加一个漏字符号(^)，在该行右边的横线上写出该加的词。
     3. 该行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。

Anita Mei was very famous pop singer in Hong Kong. Together
with her mother, she began to perform in the age of four. In the
early 1980s, she took part in a local sing competition and won the
first prize. The song "Bad Girl" made him famous. The following
years saw Anita make many records. Some of her song were very
popular. She was always ready to help others, but she made a lot
of good friends. When SARS hits Hong Kong, she organized
several concerts with other pop stars call on Hong Kong people
to brave face the disease. Sadly, Anita died of cancer in 2003. The
brave or beautiful lady will always be remembered by people.

1. _____
2. _____
3. _____
4. _____
5. _____
6. _____
7. _____
8. _____
9. _____
10. _____

单项选择题

图4-45所示结构直杆BC，受载荷F，g作用BC=L，F=qι，其中g为均布载荷，集度单位为N/m，集中力以N计，长度以m计，则该主动力系对O点的合力矩为（）。

A.

B.

C.

D.