1 . To prevent the deserts coming near, China has planted billions of trees---to replace destroyed forests and as barriers against the sand. This isn’t a cure, though, say experts, as thirsty trees can make the problem worse by taking in groundwater.
“Planting trees is one way, but it isn’t that simple. It doesn’t solve the basic issue of water resources,” says Wu Bo, a professor. “We need to calculate how much water the trees will absorb, or else it could have a negative effect.”
Villagers in Zhengxin have taken on this challenge, with limited success. When the irrigation channels began to run dry, Lu Xianglin switched from wheat to cotton on his land. He also planted trees to protect his fields from sandstorms. He says he still gets good yields（产量） using flood irrigation and earns a good income for his family.
Other farmers haven’t stuck it out（坚持到底）: about one in three have left Zhengxin in the past 10 years after their wheat crops died. Young people who can find jobs in the towns rarely return.
Last week, Mr Lu joined the other men in his village on a government-arranged trip to see the land that has been set aside for their relocation, nearly 40 miles to the south. The next day, he was back, shaking his head at the plan. The idea of uprooting his family troubles him, as does the idea of giving up the land that fed his forefathers. He prefers to stay and keep up the fight.
“With enough water, this problem can be solved,” Lu says. “We can plant trees and grass, and they will grow bigger. That will stop the desert.”
Experts say that farmers could switch to drip irrigation （滴灌）to lessen their water intake for growing crops. Elsewhere in the region, farmers have built brick greenhouses as part of a plan to grow vegetables using less water. Roadside signs urge farmers to “Save Water, Protect the Environment”.
1. The negative effect of planting trees in deserts is that __________.

A．it can make groundwater become less

B．it can prevent the sand moving freely

C．it can stop crops growing well

D．it can get the soil to become poor

2. Why did Mr. Lu NOT accept the idea of relocation?

A．Because the plan of relocation will cost him much money.

B．Because his family had trouble moving away.

C．Because he was reluctant to give up his land.

D．Because he would rather stay than fight against the deserts.

3. What can we infer from the passage?

A．The deserts drive more and more people to leave their homes for their lives.

B．People have no means to fight against the land becoming desert.

C．Water is the biggest barrier for people to stop the desert.

D．Planting trees cannot solve the problem of desertification of farmland.

4. What advice is given by experts to save water?

A．To plant more trees.

B．To build greenhouses.

C．To change crops.

D．To use drip irrigation.

2 . Energy goes from one plant or animal to another. A food chain shows how this energy moves. Each time an animal gets eaten, its energy is passed onto the animal that eats it. The food chain is very important because it keeps the balance of nature. If one part of the food chain disappears, it can affect all the other plants and animals. Any threat to the food chain is a threat to the environment’s biodiversit(生物多样性). The food chain helps keep animal populations in balance. However, if something happens to increase or decrease one of the links in the food chain, that balance is broken. If one animal becomes endangered, it puts all the animals above it at risk.
Some of the threats are natural, such as wildfires, hurricanes, tornados, floods and so on. But the biggest threats to the food chain come from you and me. These threats include overhunting, overfishing, logging, farming, development, pollution, etc. The food chain is endangered anywhere humans have had an effect on the natural environment.
A recent study shows that the overfishing of large sharks is damaging the food chain along the US Atlantic coast. Canadian and American scientists say sharks are being killed in great numbers for their meat and fins(鳍). Now, not enough sharks are around to eat the cownose(牛鼻) ray. The ray’s population has increased and they have eaten up the shellfish to the point where it has hurt commercial(商业的) fishing.
Many of us disturb the natural environment in our own backyards. It’s up to us to take care of the environment and try not to disrupt the natural food chain. If we don’t act responsibly, animals will start disappearing.
1. What can we learn from Paragraph 1?

A．The food chain is not easy to be broken.

B．The energy of an animal usually disappears when it dies.

C．Increasing the links will not break the balance of nature.

D．Breaking the food chain is bad for the biodiversity of the environment.

2. The study mentioned in Paragraph 3 proves that            .

A．human activities can be a big threat to the food chain

B．we are all responsible for the breaking of the food chain

C．natural disasters are hard to break the food chain

D．hunting large sharks for meat is beneficial

3. We can infer that the writer wrote this passage mainly to           .

A．explain what the food chain is

B．tell us something interesting about Nature

C．suggest that we stop eating meat to save animals

D．suggest that we not disrupt the natural food chain