某人用392牛的力竖直向上提质量为30千克的物体,他能否提起?物体受到的合力是多

题型:问答题

问题:

某人用392牛的力竖直向上提质量为30千克的物体,他能否提起?物体受到的合力是多大?方向如何?

考点:力的合成与应用
题型:问答题

The one-child policy has been carried out for about 20 years .Most Chinese families have only one child. By the year 2008,the number of only children in China had already been 330 million ,which was about the population of the United States .In the next twenty years ,the only-child generation (一代人) will become the main builders of our society .No one knows how much he or she will change the world .

Only children in families often receive the best care, sometimes ,even get a lot of indulgence .Parents always try their best to satisfy their children’s needs .Those children, who are called “little emperors” ,are in danger of too much love .

However these kids often fell lonely because neither their parents nor their classmates can take the place of a brother or a sister.

It seems that only children are still not ready to do their duty .some elder only children have already graduated from college .But they still depend on their parents .They need a longer time to change for their jobs, because they were brought up in a safe environment. When their parents get older, a couple of only children will have four parents and even more grandparents to look after. It will surely be the biggest problem if they don’t well prepare to face it. 

小题1:What was the population of the U.S.A in the year 2008?

A. About 3, 300, 000.   B. About 330, 000, 000.  C. About 33, 000, 000.

小题2:In this passage the word  “indulgence” means ________.

A. 溺爱             B. 批评               C.指导

小题3: Why do only children feel lonely?

A. Their parents have no time for them.

B. They don’t have free time for activities.

C. They have no brothers or sisters.

小题4:What’s the biggest problem for the family that is made up of two only children?

A. They have to look after four parents and even more grandparents.

B. They they still depend on their parents.        

C. They need a longer time to change for their jobs

小题5:The best title for the passage is ____________.

A. Parents for Only Children  B. The Only-child Generation  C. The Only-child Policy

题型:问答题

(以下5题共用备选答案)

转化是指( )。

A.移码突变
B.基因从原来的位置转到基因组另一位置
C.外来DNA引起细胞生物学特性的改变
D.噬菌体或病毒DNA携带宿主的一部分DNA进入另一宿主
E.非移码突变

题型:问答题

控制调频器的信号的基本形式有()。

A、比例调节

B、幅值调节

C、积分调节

D、微分调节

E、脉冲调节

题型:问答题

公司歇业应当办理()。

A.开业登记

B.变更登记

C.注销登记

D.营业登记

题型:问答题

停机时间超过()天时,机组投运后3天内应进行严密性试验。

A.15

B.20

C.30

D.60

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