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问题 选择题

除下列 哪个外，生物都由细胞构成

A．动物

B．植物

C．病毒

D．人

答案

答案：C

题目分析：生物具有以下特征：1、生物的生活需要营养，2、生物能够进行呼吸，3、生物能排出体内产生的废物，4、生物能够对外界刺激作出反应，5、生物能够生长和繁殖，6、除病毒外，生物都是由细胞构成的。

点评：此题为基础题，较易，解答此题的关键是理解生物的基本特征。

单项选择题

Believe it or not，optical illusion can cut highway crashes.
Japan is a case in point．It has reduced automobile crashes on some roads by Rearly 75 percent using a simple optical illusion．Butst．ripes,called chevrons(人字形)，painted on ther rads make drivers think that they are driving faster than they really are，and thus drivers slow down.
Now the American Automobile Association Foundation for Traffic Safety in Washington D．C. is planning t。repeat Japan’s success．Starting next year，the foundati。n will paint cheyrons and。ther pattems of stripes on selected roads around the country to test how well the patterns reduce highway erashes．
Excessive(too great)speed plays a major role in as much as one fifth of all fatal traffic accidents， according to the foundation．To help reduce those accidents，the foundation will conduct its tests in areas where speed-related hazards(danger)are the greatest curves，exit slopes，traffic circles，and bridges．
Some studies suggest that straight，horizontal bars painted across roads can initially cut the average speed of drivers in half．However,traffic。ften returns to full speed within months as driVers become used to seeing the painted bars．
Chevrons，scientists say，not only give drivers the impression that they are driving faster than they reallv are but als0 make a lane appear to be narrower．The result is a longer lasting reduction in highway speed and the number of traffic accidents．

The passage mainly discusses______.

A．a new way of highway speed control
B．a new pattern for painting highways
C．a new way of training drivers
D．a new type of optical illusion
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单项选择题

关于清谈的起源，下列说法错误的是（）。

A.与汉末太学游谈相关

B.与汉代讲经传统相关

C.与汉末的清议相关

D.与汉代的官制相关
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