如图所示:水平放置的纸板M上有直径8cm的圆孔,光屏N与M相距6cm,点光源S在

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问题:

如图所示:水平放置的纸板M上有直径8cm的圆孔,光屏N与M相距6cm,点光源S在圆孔中心正上方相距6cm处,在纸板上面放一厚度为cm的玻璃砖(盖住整个圆孔)时,光屏上光斑直径为20cm,求玻璃板的折射率?

考点:光的折射定律
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经海关批准,实行集中申报的进出口货物,应当适用 ______ 实施的税率。

A.集中申报之日

B.每次货物进出口时海关接受该货物申报之日

C.填发缴款书之日

D.货物放行之日

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安全事故预防的基本要求有哪些

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An older friend once gave me a piece of advice, “Enjoy the last few weeks of college,” she said, “since college is the best time of your life.”

This was not the first time I’d heard such a statement, but with graduation fast coming close, her words especially struck me. It seemed a bit disappointing to reach one's life peak at only 22 years of age, but in her opinion, college had been one of the best times in my life so far. I made friends, took classes, and learned a great deal about myself. But I was also excited for the time after college—moving to a new city, starting a new job, and becoming a "real" person. I hoped that my great dreams were practical.

Then, last week I read a column in Real Simple Magazine called 100 Years of Attitude, in which women 100 years or older shared their life experiences and views. I noticed that none of them considered college as the "best" time of their life. Not all of them went to college, but still in most cases their teens and twenties were not the best times of their life. They said some of their favorite times were raising their children, traveling after retirement, and even enjoying their present time and age.

Enjoying one's present time and age was a clear theme of the interviews. A piece of advice given by the women was about the importance of making the best of all situations. I think it more accurate than that of my friend; I can say with certainty that if I am lucky enough to make it to 100, I refuse to spend the last 80 years of my life plummeting (跌落) downhill, or even leveling off.

I am sure that our eagerness and devotion will make us college students live a meaningful life. We will not just look backwards or miss our college days. We will look forward in excitement about continued journey uphill.

小题1:Which of the following opinions does the writer agree with?

A.College is the best time of one’s life.

B.Twenties were the best time of the old people.

C.One should make the best of all situations.

D.One should not look backwards at their college time.小题2:In the second paragraph, the writer wants to say ______.

A.her achievements in college would be the peak of her success

B.she is looking forward to living as a “real” person in college

C.she becomes more and more uneasy with graduation

D.she is satisfied with the college life but is hopeful for the future小题3:The column the writer read is mainly about those old women’s ______.

A.best time of life at youth

B.life experiences and views

C.different opinions about life

D.favorite time with best friends小题4:By saying “I refuse to spend the last 80 years of my life plummeting downhill, or even leveling off” (in Paragraph 4), the writer really means ______.

A.she will not spend the rest of her time at college

B.she will not just obtain a college level certificate

C.she will not be satisfied with what she has already accomplished

D.she will not be content with the life in the future

题型:问答题

下列加点字的释义全部正确的一组是:

A.一文不(占有) 贪得无(厌烦) 奇货可(囤积)

B.(掩饰)过饰非 一衣(连带)水 通宵达(清晨)

C.原形(最终)露 不(邀请)之客 贪赃(歪曲)法

D.令人(头发)指 (依仗)隅顽抗 怨天(归咎)人

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下列各类产业中,()占区域GDP比重最大,()处于技术最前沿,()关联性作用强,()必须超前发展。

A.基础产业

B.主导产业

C.支柱产业

D.新兴产业

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