Question

     Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back.. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.

      Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines (刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach..

      Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal's teeth.

      Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.

      Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly (多刺的) leaves, and each prickle contains poisonous venom (毒液) A single experience with this kind of plant will teach an animal to stay away from it in the future.

1.The holly plant has more spines on the lower leaves because most animals________.

  A. are not tall enough                        B. like the lower leaves only

  C. are not clever enough                 D. can get the lower leaves easily

2.To defend themselves, oak trees use________.

  A. chemical means                         B. physical means

  C. bitter chemicals                       D. sandy materials

3.How does tobacco protect itself against an attack from a caterpillar?

  A. Its leaves fight against the attack by physical means.

  B. Its roots send a messenger to discourage the caterpillar.

  C. Its roots increase the production of nicotine when it is attacked.

  D. Its leaves produce poisonous sand to drive the caterpillar away.

4.What would be the best title for this passage?

  A. Plants and Animals                     B. How Plants Defend Themselves

  C. Attacks and Defenses                   D. How Animals Eat Plant Leaves

Answer

1.D

【详解】细节题。由第二段This is because the lower leaves are easier for most animals to reach.可以看出答案要选择D。

2.B

【详解】细节题。从第三段 Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal's teeth.从中可以看出答案应该选择B。

3.C

【详解】细节题。从倒数第二段When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.从中可以看出答案应该选择的是C。

4.B

【详解】主旨大意题，要求归纳标题。做这类题一般都是运用排除法，然后选出一个最佳的答案。看哪个最符合文章的意思，同时也要考虑标题的醒目、影响、归纳性强等因素。整篇文章讲的都是关于植物是如何进行自我保护的，所以选择B。

本篇介绍了植物躲避灾害、侵害的本领，是一篇科技性的说明文。