如图所示,小球质量为m,被三根质量不计的弹簧A、B、C拉住,弹簧间的夹角均为12

题型:选择题

问题:

如图所示,小球质量为m,被三根质量不计的弹簧A、B、C拉住,弹簧间的夹角均为120°,小球平衡时,A、B、C的弹力大小之比为3:3:1,当剪断C瞬间,小球的加速度大小及方向可能为(  )

①g/2,竖直向下;②g/2,竖直向上;③g/4,竖直向下;④g/4,竖直向上.

A.①②

B.①④

C.②③

D.③④

考点:弹力的大小、胡克定律滑动摩擦力、动摩擦因数力的合成牛顿第二定律
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—Hello. May I speak to Wu Ming, please?

 小题1: 

—Hello, Wu Ming. This is Wang Hong. Sorry to ring you so late in the evening, but I’ve only just got home.

 小题2: What’s the matter?

—I’d like to ask you about some stamps. Do you still have the cock year stamp? You had it when I last saw you.

—I’m afraid I don’t have it. I sold it last week.

 小题3: 

—I’m sorry. I didn’t know you wanted it.   小题4: 

—Yes, please. Thank you. It’s very kind of you.

 小题5: 

—Thank you very much.

—Bye-bye.

A.Do you like collecting stamps so much?

B.That’s all right.

C.Sorry, Wu Ming is out.

D.Do you want me to find one for you?E. Oh, what a pity!

F. Yes, speaking.

G. OK, I’ll ring you if I have any news.

题型:选择题

I’ve changed my mind. “ I wanted to have a telescope, but now I want my dad back.” Lucien Lawrence’s letter to father for Christmas written after his schoolteacher’s father had been knifed to death outside his school gate, must have touched everyone’s heart. Lucien went on to say that without his father he couldn’t see the stars in the sky. When those whom we love depart from us, we cannot see the stars for a while.

But Lucien, the stars are still there, and one day, when you are older and your tears have gone, you will see them again. And, in a strange way, I expect that you will find your father there too, either in your mind and heart. I find that my parents, who died years ago, still figure in many of my dreams and that I think of them perhaps more than I ever did when they were alive. I still live to please them and I’m still surprised by their reactions. I remember that when I became a professor, I was so proud, or rather so pleased with myself that I couldn’t wait to cable my parents. The reply was a long time in coming, but when it did, all my mother said was “ I hope this means that now you will have more time for the children!” I haven’t forgotten. The values of my parents still live on.

It makes me pause and think about how I will live on in the hearts and minds of my children and of those for whom I care. Would I have been as ready as Philip Lawrence have been to face the aggressors, and to lay down my life for those in my care? How many people would want me back for Christmas? It’s a serious thought, one to give me pause.

I pray silently, sometimes, in the dead of night, that ancient cry of a poet “Deliver my soul from the sword, and my darling from the power of the dog.” Yet I know the death comes to us all, and sometimes comes suddenly. We must therefore plan to live forever, but live as if we will die tomorrow. We live on, I’m sure, in the lives of those we loved, and therefore we ought to have a care for what they will remember and what they will treasure. If more parents knew this in their hearts to be true, there might be fewer knives on our streets today.

小题1:. According to the whole text we can see that the first paragraph ________.

A.puts forward the subject of the text.

B.shows the author’s pity on the kid.

C.acts as an introduction to the discussion.

D.makes a clear statement of the author’ views小题2:. In the second paragraph the author mainly wants to explain to us _______.

A.how much he misses his parents now

B.why his parents often appear in his dream

C.when Lucien will get over all his sadness

D.how proud he was when he succeeded in life小题3:. What feeling did the author’s mother express in her reply?

A.Proud

B.Happy

C.Disappointed

D.Worried小题4: In the author’s opinion, the value of a person’s life is ________.

A.to leave a precious memory to the people related

B.to have a high sense of duty to the whole society

C.to care what others will remember and treasure

D.to share happiness and sadness with his family小题5:. What does the writer mean by the sentence taken from an old poem?

A.Call on criminals and murderers to lay down their guns.

B.Advise parents stay with their children safely at home.

C.Spend every day meaningfully in memory of the death.

D.Try to keep violence and murder far away from society.

题型:选择题

26岁,初产妇,妊娠39周,规律宫缩18小时,肛查宫口8cm,先露0,胎膜未破,腹部触诊为头先露,宫缩时宫体部不硬,持续30秒,间隔5分钟,胎心率136次/分,B型超声检查示胎儿双顶径为9.0cm

本例首先的处理是().

A.人工破膜

B.立即剖宫产

C.静脉滴注缩宫素5U

D.肌注哌替啶100mg

E.观察1小时后再决定

题型:选择题

哈维

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细胞壁可分几层,各由什么成分组成?

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