Question

【題目】Urban swans might be born with a daredevil gene that makes them less fearful of humans, compared with their rural colleagues.

A study has found swans living in cities tend to be bolder and it is at least partly determined by a gene called DRD4. Birds with this gene could therefore be better adapted to settling in more populated areas, while more timid（膽怯的）swans would escape to less inhabited regions.

It could help to explain why swans in public parks and on urban rivers have a reputation for being so aggressive towards humans - they are simply not afraid of us.

Biologists from some universities in Australia, tracked and collected blood samples from black swans living in two wetlands near cities. One group of swans lived in a recreational urban park, while the other occupied a waste-water processing site out of town. The two areas were less than 20 miles apart.Later, from 2011 through 2013, the researchers started systematically scaring the swans at both sites. The researchers approached the birds and calculated how close they could get before they flew away.As expected, they noticed that while rural swans started flying away if a human was closer than 119 meters, the scientists could come as close to urban swans as 39 meters before taking off.

Analyses of the blood samples, in fact, showed that 83 per cent of the less cautious swans presented the same genetic DRD4 variation（變異)while rural swans have different genetic makeups resulting in more wariness(謹慎，小心）.

The researchers conclude that swans with the bold variation of the gene might choose to live in urban environments, as they tend to be less bothered by human presence.

【1】The underlined word in paragraph 1 means__________.

A. timid B. cautious

C. bold D. stubborn

【2】What’s the difference between rural swans and urban ones？

A. The rural swans carry more DRD4.

B. The urban swans are more friendly.

C. The urban swans are less scared of people.

D. The rural swans are aggressive towards humans.

【3】What does DRD4 refer to ?

A. a kind of blood. B. a kind of food.

C. a kind of genetic variation. D. a kind of swan.

【4】What does the 4th paragraph mainly talk about?

A. The living habit of swans.

B. The living environment of swans.

C. The contribution of the biologists.

D. The process and result of the research.

Answer 1

【答案】

【1】C

【2】C

【3】C

【4】D

【解析】這是 一篇說明文。研究表明城市的天鵝身體內帶有一種變異的基因DRD4，這使得它們不太怕人類。

【1】詞義猜測題。根據下文的that makes them less fearful of humans可知，這種基因使它們不太害怕人類，所以它們非常的大膽，故選C。

【2】推理判斷題。根據第一段Urban swans might be born with a daredevil gene that makes them less fearful of humans, compared with their rural colleagues.可知，與農村的天鵝相比，城市的天鵝不太害怕人類，故選C。

【3】細節(jié)理解題。根據第五段中的the same genetic DRD4 variation可知，DRD4是一種變異的基因，故選C。

【4】段落大意題。第四段講述了澳大利亞的科學家們采集了天鵝的血液樣本進行研究，并對它們可以接受人類的距離進行了實驗并得出結論，城市的天鵝比農村的天鵝更加膽大，故選D。