中碳钢是指碳的质量分数在（）范围之内的铁碳合金。 A.0.04%～0.25% B.0

如图所示，在空间中的A、B两点固定着一对等量正点电荷，有一带电微粒在它们产生的电场中运动，设带电微粒在运动过程中只受到电场力的作用，带电微粒在电场中所做的运动可能是：

A．匀变速直线运动； B．匀速圆周运动； C．类似平抛运动； D．机械振动．

现有某同学分析如下：带电粒子在电场中不可能做匀变速直线运动与类似平抛运动，因为带电粒子在电场中不可能受到恒定的外力作用，所以A、C是错误的，也不可能做匀速圆周运动，因为做匀速圆周运动的物体所受的合外力始终指向圆心充当向心力，图示中两点电荷所产生的电场不可能提供这样的向心力，所以B也是错误的．唯有D正确，理由是在AB连线中点O两侧对称位置之间可以做机械振动．

你认为该同学的全部分析过程是否有错，若没有错，请说明正确答案“D”成立的条件？若有错，请指出错误并说明理由．

阅读理解

      Every child should have a solid science education whether they want to be the next Albert Einstein

or Michael Jordan.Science is all around us. it is everywhere. reaching everything that we do.The  "we" 

 in that last statement includes children.Children that understand how science plays a role in our everyday

lives have a wonderful foundation (基础) for success in life.

     Children can learn science at any age really.The earlier they start the better.The best way for kids to

learn is through play and repetition.There are wonderful science toys for preschool science activities.With

play being the best way kids learn. it only makes sense then to introduce toys to them that encourage

understanding science.Children love to use their imagination to have fun and to help them understand the

world around them.So play is a wonderful time to be introducing science to them.Think of the games that we used to play:Don't Spill the Beans. Don't Break the Ice. the Telephone Game. Lincoln Logs. each of

these games has science behind it.

     Children are by nature curious (好奇的) as they feel out the world. trying to make sense of what is

around them.Science feeds that curiosity that they have.It is a hunger that needs to be encouraged and

satisfied.Finding these toys is not as hard as one would think.To make sure that you get good quality toys. visit science toy shops online.These are the best places to find unique (独特的) science toys such as 3D

space projectors. or Hydro Greenhouses.

      Help your children appreciate the world around them by understanding the world around them.This

way. they understand how we are all connected together.Children will not only question the world. but

be able to come up with answers to those questions on their own.Science is life.

1. Children should have a good science education because________.

A. they want to be famous scientists in the world

B. it can help them to make a large amount of money

C. it plays a decisive role in their daily lives

D. it is hepful to their success in the future.

2. According to the passage. which of the following is TRUE?

A. Science is hardly connected with our daily lives.

B. Children learn science best through playing.

C. Children learn science using their hands.

D. Parents should encourage their children to study hard.

3. Don't Spill the Beans. Don't Break the Ice. the Telephone Game and Lincoln Logs are

    the games________.

A. that are the most widely played

B. that can introduce science to children

C. that most students like to play at school

D. that keep children strong and healthy

4. The third paragraph is mainly to tell us that________.

A. children are born curious about the world

B. it is necessary to feed children in time

C. science toys can satisfy children's curiosity

D. most of the toys online are very cheap

5. The text is most probably written for________.

A. parents  

B. scientists  

C. children          

D. teachers

网站规划的主要任务是什么？

简述劳资沟通的方法和技巧。

在Word编辑文档时，每个段落结束处有一个段落标记，它是通过（）得到的

A、按空格键

B、按回车键

C、按End键

D、输入句号