什么叫发光?根据发光持续时间的长短把固体发光区分为几种类型?

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问题:

什么叫发光?根据发光持续时间的长短把固体发光区分为几种类型?

考点:环境科学技术及资源科学技术稀土资源稀土资源题库
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某工厂原来每天生产100个零件,现在工厂要在12天内生产一批零件,只有每天多生产10%才能按时完成工作,第一天和第二天由于部分工人缺勤,每天只生产了100个,那么以后10天平均每天要多生产百分之几才能按时完成工作()

A.12%

B.13%

C.14%

D.15%

题型:问答题 简答题

根据句意及首字母提示在横线处填上恰当的单词,使句子意思完整,语法正确。

1. The desserts are very delicious. Have you t_______ them?

2. The price of the car is i_______ so fast that I can't afford it.

3. He is a v_______, so he eats mainly vegetables.

4. —How well Mary sings!    

    —Yes.  She has a s_______ voice.

5. Be careful when you cross the m_______ road because there are many people and cars on it.

6. Lei Feng,  a great soldier,  will live in everyone's h_______ forever.

7. You can't e_______ to learn a foreign language in two months.  That's impossible.

题型:问答题 简答题

阅读短文,根据短文内容及首字母提示,在空白处填入一个适当的单词。

One day a farmer’s donkey (驴) fell down a well (井). The animal cried for hours as the farmer tried to find a way to get it out. Finally, he d____86____ to give up the animal, because it was very old and the well needed to be covered up.

He invited all of his neighbours to come and help him. They all began to fill the well w____87____ dirt (泥土). The donkey realized what was h____88____ and began to cry. Then, to everyone’s surprise, it became quiet.

A few minutes l____89____, the farmer finally looked down the well. He was a____90____ at what he saw. With each shovel (铲) of the dirt that hit its b____91____, the donkey shook it off and took a step up.

As the farmer’s neignbours went on to shovel dirt on top to the animal, he s____92____ shook it off and took a step up. Pretty soon, the donkey h____93____ got out.

Life is going to shovel dirt on you, all kinds of dirt. E____94____ of our troubles is stepping stone. You can g____95____ out of the deepest well just by not stopping and never giving up! Shake (摇) it off and take a step.

题型:问答题 简答题

内基小体在哪种疾病的诊断中有重要意义()

A.狂犬病

B.天花

C.麻疹

D.疱疹

E.腮腺炎

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湿藏法是将种子置于()条件下贮藏称为湿藏。

A、干燥

B、通气

C、低温

D、湿润

E、室温

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