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-19th 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

There was a kingdom long, long ago. It was ruled by a king who loved riddles. Once a year the king made a new riddle. He gave a prize to the person who could solve the riddle.

There was a baker who also lived in this kingdom. Everyone agreed that he baked the finest breads. The baker had almost everything he needed except for a horse. If the baker had a horse, he could sell his fine breads from one end of the kingdom to the other.

One year the king made a new riddle that puzzled everyone. "I will give a prize to the person who can solve my riddle, "the king said. "Whoever wins will have the pick of one of my strongest horses." He then drew a line down the middle of the courtyard. "Make this line shorter without erasing (清除) any part of it," the king challenged.

People came from far and wide. They looked at the line and squinted at it. They even put their noses to the ground and scratched their heads.

"How can you make a line shorter without erasing any part of it?" the people in the crowd asked each other. Some of them tried. The dressmaker kicked dirt (泥土) over the line to hide it. The farmer poured water over the line to make it disappear. None of these efforts worked, and the people went home disappointed. Everyone was puzzled about how to solve this new riddle.

A week passed, and nobody had any new ideas. Then one day the baker came into the courtyard with a bag of flour (面粉).

"Your Majesty," the baker said to the king, "I can make your line shorter without erasing any part of it." Then the baker opened his bag of flour. He poured out a line of flour right next to the king's line. The line the baker made was longer than the king's line.

"Now, good king," the baker smiled, "your line is shorter."

The people were amazed. The king laughed and clapped his hands. "You have won the prize. I will give you a horse of your choice."

The baker was excited. Now he could sell his breads from one end of the kingdom, to the other.

1.What was the baker's problem at the beginning of the story?

A.He couldn't make fine breads.

B.He needed money to open more stores.

C.He didn't have enough flour to make more breads.

D.He had difficulty selling breads all over the kingdom.

2.The dressmaker and the farmer failed because they both ________.

A.tried to erase the line. B.poured water over the line

C.kicked dirt over the line D.put their noses to the ground

3.The baker smiled because ________.

A.he was glad to see the king B.he wanted to make the king happy

C.he felt sure that he solved the riddle D.he sold a lot of breads to the villagers

4.This story shows that the king liked ________.

A.to be rich B.to draw a line C.to eat breads D.to have fun

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