问题 选择题

保护色对生物的作用不是(  )

A.引起敌害警觉而被吓跑

B.不易被其它动物发现

C.有利于躲避敌害

D.有利于捕食猎物

答案

动物的体色与周围环境的色彩非常相似,这种体色称为保护色.生物具有保护色可以不易被其它动物发现,有利于躲避敌害,有利于掩护自己捕食猎物;警戒色是指某些有恶臭和毒刺的动物和昆虫所具有的鲜艳色彩和斑纹.这是动物或植物在进化过程中形成的,可以使敌害易于识别,避免自身遭到攻击.如毒蛾的幼虫,多数都具有鲜艳的色彩和花纹,如果被鸟类吞食,其毒毛会刺伤鸟的口腔粘膜,这种毒蛾幼虫的色彩就成为鸟的警戒色.因此引起敌害警觉而被吓跑属于警戒色,不是保护色的特点.

故选:A

单项选择题
阅读理解

阅读理解。

     It is well-known that it will take travelers only 48 hours by train to go from Beijing to Lhasa, the capital

of west China's Tibet on July 1 this year. Travelers can enjoy the beautiful views during the 48 hour train ride.

     The new railway line will be controlled by the Beijing's West Railway Station from July 1, 2006. The most

important part of the line, the Qinghai-Tibet Railway, has been completed.

     The Qinghai-Tibet part of the railway is the world's highest railway. About 960 kilometers of the train

tracks are 4,000 meters above sea level. The highest parts reach 5,072 meters.

     The railway is the world's longest plateau railroad which is 1,956 kilometers long, from Qinghai's capital

Xining to Lhasa in Tibet. The Glommed-Lhasa part is 1,142 kilometers long and goes across the Kunlun and

Tangelo mountain ranges.

     The trains running on the Qinghai-Tibet Railway have very good conditions. If the passengers feel hard to

breathe, they will be provided with oxygen masks, because all of the trains have oxygen supplying equipments.

1. It will take people 48 hours by train to go to Lhasa from Beijing _________.

A. from now on

B. next July 1

C. from July 1, 2006

D. from July 1, 2005

2. When we talk about the Qinghai-Tibet part of the railway, we say _________.

A. the railway is well-known

B. the railway is the highest

C. it is easy to operate

D. it was completed easily

3. The highest parts of Qinghai-Tibet Railway reach _________ meters.

A. 960

B. 4,000

C. 5,072

D. 1,956

4. In the last paragraph, the phrase "oxygen masks" means _________. 

A. 氧气面罩

B. 望远镜

C. 热水

D. 药品

5. The best title of the passage is _________.

A. Travel from Beijing to Lhasa

B. Qinghai-Tibet Railway

C. Train with Best Conditions

D. Well-Known Railway