Question

    Spring is here, the colourful flowers are seen everywhere but it is a pity that many of us are not able to smell them while enjoying the colourful flowers.

Growing levels of air pollution from the factories and cars have reduced flower fragrances(芳香) by up to 90 percent in the US, compared with pre-industrial levels 100 years ago.

But if the trend is simply unpleasant for human noses, it may be life-dangerous for bees and butterflies.

Many insects find flowers by following the scent produced by those flowers.

The increasing pollution makes it difficult for them to find the flowers and feed on their nectar (花蜜).

Scientists have already found that flowers produce scent molecules (气味分子) that mix with polluted things, which breaks down the plants’ sweet smell.

With more pollution in the air, the scent molecules don’t remain powerful as long and travel shorter distances on the wind. In the mid-19^th century, when pollution levels were first recorded, scent molecules would have been able to travel some 1,000 to 1,200 meters. Today, in the polluted air of large cities, scents may only make it some 200 to 300 meters.

Also, pollution from polluted air may fool the bee’s “nose”, making their search for flowers all the more difficult.

In a paper published recently in Scientific Reports, scientists said that the nitric oxide (NO) and nitrogen dioxide (NO2) in polluted air could change many chemicals that work together to give a flower its special smell.

“This”, researchers said, “could prevent honeybees from reaching their flowers and prevent the pollination (授粉) of some of the world’s food crops.” Or, this could put in danger agricultural harvests worldwide.

But the bees seem to have learned to get used to the changing world. “In nature honeybees use their special eyes and flower smell to find out where a flower is for the first time,” the researchers said.

1.According to the article, researchers have recently found that ________.

A.reduced flower fragrances have resulted in the dying out of many bees and butterflies

B.reduced flower fragrances are connected to growing levels of air pollution

C.polluted things in the air prevent flowers from producing scent molecules

D.flowers today can’t produce enough nectar because of air pollution

2.What do the underlined words “the trend” in Paragraph 3 refer to (指的是)?

A.Increasing air pollution.

B.Reduce flower fragrances.

C.Human beings’ worse sense of smell.

D.A growing number of power plants and cars.

3.The scent molecules a plant produces are mainly to ________.

A.help flowers to produce nectar B.prevent insects from eating the plant

C.draw attention from bees and butterflies D.clear up polluted things in the air

4.We can infer (推断) from the article that ________.

A.future food crops won’t depend on bees to complete their pollination

B.bees have great advantages in their senses compared to humans

C.world food crop production is likely to fall greatly in the near future

D.some bees have successfully get over the challenge of reduced flowers fragrance

Answer

1.B

2.B

3.C

4.D

【解析】

这篇文章主要讲述了随着社会的发展，工厂和汽车造成的空气污染不仅使得人们在赏花时很难闻到花香，更对动物界的蜜蜂和蝴蝶产生了重大的影响，可能危及全世界的农业收成。地球是我们唯一的家园，这也启示我们要保护环境，爱护环境，人与自然要学会和谐共处。

1.细节理解题，根据文章中“Growing levels of air pollution from the factories and cars have reduced flower fragrances 工厂和汽车产生的日益严重的空气污染降低了花香”可知花香的减少与空气污染水平的提高有关，故选B。

2.推理判断题，根据“is simply unpleasant for human noses 让人类的鼻子不舒服”与上文“it is a pity that many of us are not able to smell遗憾的是我们很多人都无法闻到”综合分析可知与花香的减少有关。另外根据the trend后一句中“it may be life-dangerous for bees and butterflies. 对蜜蜂和蝴蝶来说，这可能有生命危险。”可知此处的it也是指代的the trend，结合下文讲述许多昆虫都是通过跟随花朵产生的气味来找到花朵的，但日益增加的污染使他们很难找到花朵并以花蜜为食可推断出此处的the trend应该指的是花香的减少，故选B。

3.细节理解题，根据文中“Many insects find flowers by following the scent produced by those flowers. 许多昆虫都是通过跟随花朵产生的气味来找到花朵的。”可知植物产生的气味分子主要是吸引蜜蜂与蝴蝶的。故选C。

4.推理判断题，根据原文最后一段可知一些蜜蜂已经成功克服了减少花香的挑战，故选D。原文虽然提及“Or, this could put in danger agricultural harvests worldwide. 否则，这可能会危及全世界的农业收成。”但并没有说未来的粮食作物将不会依靠蜜蜂完成授粉，世界粮食作物产量可能在不久的将来大大下降，故A选项和C选项错误，B选项文章没有提及。故选D。