在水平面上有一质量为1kg的长方体。用4N的水平拉力向右拉,长方体静止不动,此时

题型:填空题

问题:

在水平面上有一质量为1kg的长方体。用4N的水平拉力向右拉,长方体静止不动,此时它所受的摩擦力为        N;拉力增大至6N时长方体做匀速直线运动;若拉力增大至8N时长方体所受的摩擦力为        N。

考点:力的概念
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原子失去最外层电子或最外层得到电子,一定不会引起改变的是(  )

A.核外电子总

B.电子层数

C.化学性质

D.元素的种类

题型:填空题

加工中心刀具的存取方式有顺序方式和()方式。

题型:填空题

--Let’s meet          the morning of September 5.

--OK.

A.in

B.at

C.on

D.for

题型:填空题

Mr Smith is an English man. He teaches English well. His English classes are very interesting. He likes us and we like him, too. Mr Smith has two children-Tom and Mary. Tom is seven and his sister, Mary, is four. Tom goes to school but Mary doesn't. Mr Smith likes wearing a T-shirt and jeans(牛仔裤). Football is his favorite sport. After school we often have a baseball match. Sometimes Mr Smith watches and joins us. He plays baseball just for fun.

小题1:Mr Smith is ______.

A.a Chinese teacher

B.an English driver

C.a Japanese teacher

D.an English teacher小题2:How many sons does Mr Smith have?

A.Only one.

B.Two.

C.Three.

D.Not many.小题3:Mary doesn't go to school because ______.

A.she looks beautiful

B.she is seven

C.she is only four

D.she doesn't like school小题4:______ is Mr Smith's favorite sport.

A.Baseball

B.Football

C.Running

D.Volleyball小题5:The story (故事) is about ______.

A.Mr Smith's son

B.Mr Smith

C.Tom and Mary

D.a basketball

题型:填空题

引起慢性肾功能衰竭的最常见病因是()。

A.慢性肾盂肾炎

B.慢性肾小球肾炎

C.肾结核

D.肾小球硬化症

E.慢性尿路梗阻

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