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问题 选择题

如果农田中某种野草在地球上永远消失，对人类有何影响（　　）

A．没有任何影响

B．生态系统更加稳定

C．提高农作物产量

D．丧失一个基因库，其潜在价值消失

答案

生物多样性通常有三个主要的内涵，即生物种类的多样性、基因（遗传）的多样性和生态系统的多样性．基因的多样性是指物种的种内个体或种群间的基因变化，不同物种（兔和小麦）之间基因组成差别很大，生物的性状是由基因决定的，生物的性状千差万别，表明组成生物的基因也成千上万，同种生物如兔之间（有白的、黑的、灰的等）基因也有差别，每个物种都是一个独特的基因库，某种野草在地球上永远消失，那么这个物种的基因库也就消失了，其潜在价值消失．潜在价值．今天还未被利用的哪些物种在将来会有利用的价值．

故选：D．

阅读理解

There are about fifteen hundred languages in the world。But only a few of them are very important．English is one of these．Many people use it，not only in England and the USA，but also in other parts of the world．About 200，000，000 people speak it as their own language．It is difficult to say how many peopie are learning it as a foreign language．Many millions of people are trying to do so．Is it easy or difficult to learn English?Different people may have different answers．Have you ever noticed ads(广告)of this kind in the newspapers or magazines?“Learn English in six weeks，or give your money back…”，“easy and funny…”，“Our records and tapes help you master English in a month”．Of course，it never happened quite like this．

The only language that seems easy to learn is t11e mother tongue．We should remember that

we all learned our own language well when we were children．If we could 1ea m English in the

same way，it would not seem so difficult．Think of what a small child does．He 1istens lo what people say．He tries what he hears．

So，it is hard to say that learning English is easy．We must do a Iot ofpractice．And practice needs great effort and takes much time．Good teachers，records，tapes，books，and dictionaries will be helpful，but they cannot do the student’s work for him．

小题1:How many languages are very important in the world?

A．A few．

B．Few．

C．About 1，500．

D．Many．小题2:How does the writer like the ads in the newspapers or magazines?

A．He thinks the ads very expensive．

B．He thinks the ads are true．

C．It never happened quite like what the ads said．

D．He believes“Learn English in six weeks，or give your money back．”小题3:Which language is easy to learn?

A．English．

B．Chinese．

C．Japanese

D．The mother language．
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多项选择题

19世纪由于建立了电磁理论，从而创造了发电机、电动机，使人类进入了电气化时代。这一历史事实说明( )。

A．科学理论与实践相结合，可以转化为物质力量

B．科学理论是认识的基础，对实践起决定作用

C．科学理论的任务不仅在于认识世界，而更重要的在于改造世界

D．科学理论可以指导实践
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