电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接

题型:选择题

问题:

电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接在滑轮组上.滑轮组由a、b、c三个滑轮构成,配重P由多个混凝土圆盘悬挂在一起组成,配重的总重为G,若不计摩擦和滑轮的重量,则以下说法中正确的是(  )

A.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

B.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

C.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

D.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

考点:定滑轮及其工作特点动滑轮及其工作特点
题型:选择题
方程组
x
3
=2-
y
2
y+1
4
=
x
5
-
3
4
可以化简为(  )
A.
2x-3y=12
4x+5y=20
B.
2x+3y=2
4x+5y=20
C.
2x-3y=2
4x-5y=20
D.
2x+3y=12
4x-5y=20
题型:选择题

科学研究表明,本世纪初的两年是太阳活动最剧烈的一段时间。太阳风暴以每小时300万千米的速度向地球扑来,与地球磁场发生碰撞产生地球冲击波,不仅对卫星通信、地面通信、供电设备等造成一定的干扰,而且能使人体免疫力下降,皮肤容易被强烈紫外线辐射灼伤,使心血管系统病人病情加重,还能影响胎儿生长和孩子智商。科学家对太阳活动规律的把握说明(  )

A.人类能够充分发挥主观能动性认识世界

B.只要充分发挥主观能动性,就能认识一切事物

C.量的积累达到一定程度必然引起质变

D.我们要透过现象抓住事物的本质和规律

题型:选择题

常用于养殖场带畜禽消毒药物是()

A.2%氢氧化钠

B.5%苯扎溴铵

C.0.3%过氧乙酸

D.1%次氯酸钠

E.1%甲醛

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Writing a long book seemed to be too much for me. So, for a long time, I just wrote short articles. One day, inspiration(灵感) for an article hit me and, as I started writing, paragraphs began flowing out fast. It turned out to be too long to be an article. I thought it would not hurt to try self-publishing a booklet(小册子). The first printing of this 32-page black and white booklet sold out within a week. Here is something that I have learned through my experience.

1.Start small.

Don’t try to have a 400-page work as your first publication. I suggest you publish a booklet under 50 pages to launch your career as an author.

2.Ask for advice.

If you know some people who have published something, ask them for advice and help. You will gain useful information from them and save yourself many problems.

3.           

When you put your heart into something only to hear“We’re not interested”,you may get hurt. But you must remind yourself that this is quite common. Every“yes”you receive comes after at least five“noes”,especially at the beginning. You need to revise your book many times to reduce the chances of being turned down.

4.The more you market, the more you sell.

You can publish an excellent book. But if no people know about it, you cannot expect many buyers. Send out an e-mail to friends, family and business partners, telling them your book’s publication date. Ask them to help sell your book.

Do not be afraid to try novel ideas.

小题1:What does the underlined word“launch”in Point 1 there mean?

A.Begin.

B.Develop.

C.Lead.

D.Describe.小题2:What’s the best title for Point 3?

A.No one will like what you wrote at first.

B.You will get hurt by what you wrote at first.

C.Prepare for a“yes”rather than a“no”.

D.Be prepared to deal with“noes”.小题3:According to the passage, if you want to have more copies of your book sold, you should      .

A.advertise your book in newspapers

B.try to make more people know your book

C.ask your business partners to buy your book

D.write something that people are interested in小题4:About self-publishing a book, the writer would most probably agree that       .

A.one usually makes no money out of self-publishing a book

B.one should never self-publish a book longer than 400

C.self-publishing a book is impossible for most people

D.asking advice from people who have published a book is helpful

题型:选择题

在面向对象方法中,类的实例称为______。

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