阅读理解

Passage 2

Questions 16—20 are based on the following passage.

Researchers studying animal behaviour have recently started noticing something unusual.Some animals were observed to be eating plants that are not part of their normal diet and have nonutritional value. They ate these plants at only some times of the year while other animals in thegroup did not eat the same plants. What can account for this odd behaviour?

The researchers believe that these animals are giving themselves medicine. These plants canmake the animals feel better, kill parasites(寄生虫)or aid in digestion. Many different animalshave been observed acting in this way. Some chimps in a nature reserve in Tanzania had parasites which caused them stomach upsets. They were seen chewing and swallowing the leavescontaining special medicines. These leaves were rough with sharp spikes sticking out. Scientiststhink that these rough leaves were eaten to clean out the insides of the chimps' stomachs so thatthe parasites would be killed.

Other examples of animals self-medicating include lizards which respond to the bite of avenomous(有毒的)snake by eating a special root that can counter(对抗)the poison,and macawbirds(金刚鹦鹉)that eat clay to aid in digestion and kill bacteria. Pregnant elephants have beenknown to eat the leaves of some trees as a way of speeding up the delivery of their babies.

How did animals learn this behaviour? The most obvious answer is that animals learnt byexperience. For example, a gorilla once felt ill, ate some leaves and then felt better the next day.It remembered this and passed on this information to the rest of the group and its children. Butwhat about creatures that are less intelligent? Scientists studying the monarch butterfly(黑脉金斑蝶)noticed that some healthy butterflies laid eggs on the milkweed plant which has anti-parasite properties. These eggs produced strong healthy butterflies compared to the ones hatchedon plants that do not have such medicinal benefits. Over time the weaker butterflies producedfewer eggs and the healthy butterflies thrived(茁壮成长). This is an example of naturalselection.

If we can learn from animals using plants to heal and protect themselves naturally, we toomight gain medicinal benefits.

单选题 ( )In writing Paragraph 1, the author aims to________.

A、 bring up a topic
B、 reach a conclusion
C、 make a comparison
D、 propose a definition

【正确答案】 A

【答案解析】推理判断题。根据第一段最后一句Whatcan account for this odd behaviour(怎样解释这种奇怪的行为呢)可知，作者写第一段的目的是通过设问来提出话题。故选A。

单选题 ( )What can we learn from the passage ?

A、 Chimps sometimes eat special leaves to ease stomach problems.
B、 Macaw birds are the only birds that use plants to kill bacteria.
C、 Lizards eat special roots to speed up the laying eggs.
D、 Pregnant elephants use leaves to aid in digestion.

【正确答案】 A

【答案解析】推理判断题。根据第二段中的Some chimps in a nature reserve in Tanzania had parasites which caused them stomach upsets.. so that theparasites would be killed可知，黑猩猩有时会吃一些特殊的叶子来治疗胃病，故选A。

单选题 ( )A gorilla learnt the self-medicating ________.

A、 by avoiding hunters
B、 by making imitations
C、 by gaining experience
D、 by countering the poison

【正确答案】 C

【答案解析】推理判断题。根据第四段第二句和第三句The most obvious answer is that animals learntby experience. For example, a gorilla once felt ill, ate some leaves and then felt better the nextday可知，大猩猩学会自我治疗是通过积累经验。故选C。

单选题 ( )According to Paragraph 4, we know the monarch butterfly seemed likely to________.

A、 use an anti-parasite liquid to protect the eggs
B、 lay eggs on the milkweed plants to avoid the snake
C、 produce strong healthy eggs on the clay in Tanzania
D、 have healthy kids by laying eggs on the milkweed plants

【正确答案】 D

【答案解析】推理判断题。根据第四段中的some healthybutterflies laid eggs on the milkweed plant.. thatdo not have such medicinal benefits(一些健康的蝴蝶在具有抗寄生虫特性的乳草筋植物上产卵，与在没有这些药用益处的植物上孵化的蝴蝶相比，这些卵产生了强壮的健康的蝴蝶)可知，黑脉金斑蝶通过在乳草筋植物上产卵来拥有健康的后代。故选D。

单选题 ( )What can we infer from the last paragraph?

A、 We may get benefits from the study of animals' self-medication.
B、 We should make use of the study to protect the environment.
C、 The study of animals' self-medication is not important.
D、 Animals' self-medication has set an example for us.

【正确答案】 A

【答案解析】推理判断题。根据最后一段可知我们可以学习动物利用植物来治愈和保护自己，从而获得药用益处。故选A。