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问题 单项选择题

根据能量意外释放理论，能量逆流于人体造成的伤害分为两类。其中，第二类伤害指（）。

A.由于施加了局部或全身性损伤阈值的能量引起的伤害，如物体打击伤害等

B.由影响了局部或全身性能量交换引起的伤害，如中毒伤害等

C.由于能量超过人体的损伤临界值导致局部或全身性的伤害，如冻伤等

D.由于接触的能量不能被屏蔽导致的局部或全身性的伤害，如触电伤害等

答案

参考答案：A

选择题
如图所示为一磁流体发电机示意图，A、B是平行正对的金属板，等离子体（电离的气体，由自由电子和阳离子构成，整体呈电中性）从左侧进入，在t时间内有n个自由电子落在B板上，则关于R中的电流大小及方向判断正确的是（　　）

A．I= ，从上向下

B．I= ，从上向下

C．I= ，从下向上

D．I= ，从下向上
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单项选择题

(四)

The average person learns most of the 30000 ～40000 words whose meanings he or she recognizes by hearing them or getting familiar with them in the context or simply absorbing them without conscious effort. The best way to build a good vocabulary, therefore, is to read a great deal and to participate in a lot of good talks. There are relatively few words that we learn permanently by purposefully referring to dictionaries or keeping word lists. However, even those extra few are of value, and no one will make a mistake by working on developing a larger vocabulary. Here are some suggestions of how to do it.

Read plenty of good books. When you come across a new word, or a new meaning of an old word, stop and see if you can understand it from its context. If you can’t, and if you can manage without interrupting the thought of the book too much, look it up in a dictionary or ask somebody and then repeat its meaning to yourself a couple of times, If you are really conscientious, write the word and its meaning in a personal vocabulary list—preferably using it in a sentence, or you can keep a special vocabulary notebook. Go over the list from time to time. Further, try to use a new word in writing or conversation a few times over the next several days.

Listen to good talks and be alert to new words you hear or to new meanings of words you already know. Then treat them just as you treat the new words you read.

Learn and be alert to the parts of words: prefixes, suffixes and roots. Knowing them enables you to make intelligent guesses about the meaning of words.

If you are studying a foreign language, be alert to words in that language which relate to words in English. English has inherited or borrowed much of its vocabulary of 500000～600000 words from Latin, Greek, French, Spanish and German.

The phrase "be alert to" in the third paragraph may best be replaced by "（）".

A．look at

B．pay attention to

C．write down

D．learn by heart
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