在晚秋或寒冬,用人造烟幕来防御霜冻的原理是[ ] A、增强太阳短波辐射 B、增强

题型:选择题

问题:

在晚秋或寒冬,用人造烟幕来防御霜冻的原理是[ ]

A、增强太阳短波辐射

B、增强大气逆辐射作用

C、增强大气对太阳辐射的散射作用

D、增强大气对太阳辐射的反射作用

考点:大气的受热过程
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下列哪一种氨基酸在生理条件下含有可解离的极性侧链()

A.Ala

B.Leu

C.Lys

D.Ser

E.Phe

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下列有关生物碱的论述,正确的是()

A.含有N原子

B.均显碱性

C.包括来源于自然界的所有含N成分

D.无色

E.均具有复杂的环状结构,N原子在环内

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It was Monday. Mrs. Smith's dog was hungry , but there was not any meat in the house.

Considering that there was no better way. Mrs. Smith took a piece of paper, and wrote the following words on it:“Give my dog half a pound of meat.”Then she gave the paper to her dog and said gently:“Take this to the butcher(* person whose job is selling meat)and he's going to give you your lunch today.”

Holding the piece of paper in its mouth, the dog ran to the butcher's. It gave the paper to the butcher. The butcher read it carefully, recognized that it was really the lady's handwriting and soon did it as he was asked to. The dog was very happy, and ate the meat up at once.

At noon, the dog came to the shop again. It gave the butcher a piece of paper again. After reading it, he gave it half a pound of meat once more.

The next day, the dog came again exactly at noon. And as usual, it brought a piece of paper in the mouth. This time, the butcher did not take a look at paper, and gave the dog its meat, for he had regarded the dog as one of his customers.

But, the dog came again at four o'clock. And the same thing happened once again. To the butcher's more surprise, it came for the third time at six o'clock, and brought with it a third piece of paper. The butcher felt a bit puzzled . He said to himeself,“This is a small dog. Why does Mrs. Smith give it so much meat to eat today?”

Looking at the piece of paper, he found that there were not any words on it!

小题1:Mrs. Smith treated her little dog quite     .

A.cruelly

B.fairly

C.kindly

D.friendly小题2:It seemed that the dog knew well that the paper Mrs. Smith gave it    .

A.might do it much harm

B.could do it much good

C.would help the butcher

D.was worth many pounds小题3:The butcher did not give any meat to the dog     .

A.before he felt sure that the words were really written by Mrs. Smith

B.when he found that the words on the paper were not clear

C.because he had sold out all the meat in his shop

D.until he was paid enough by Mrs. Smith小题4:From its experience, the dog found that     .

A.only the paper with Mrs. Smith's words in it could bring it meat

B.the butcher would give the meat to it whenever he saw it

C.Mrs. Smith would pay for the meat it got from the butcher

D.a piece of paper could bring it half a pound of meat小题5:At the end of the story, you'll find that    .

A.the dog was clever enough to write on the paper

B.the dog dared not go to the butcher's any more

C.the butcher was told not to give any meat to the dog

D.the butcher found himself cheated by the clever animal

题型:选择题

在2008年北京奥运会上,中国体育代表团共获得了()块金牌,居金牌榜首位。

A.51

B.52

C.53

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机冷车组发生故障临修时有何规定?

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