London: What could possibly he wrong with planting trees? The benefits are obvious: they firm the soil, absorb extra water and take carbon dioxide out of the atmosphere.

However, it now turns out that planting trees could add to global warming. Tree roots do a great job of keeping soil firmly on the ground and out of the wind's power. The problem is that some of those dust clouds play an important part in taking in carbon dioxide.

Huge dust storms blow out over the oceans from dry parts of North Africa and central Asia. Tons of dust are lifted and left as a thin film over the ocean surface.

Dust from China is carried east and left in the Pacific Ocean. If a tree-planting program there is successful and the dust supply reduced, the final result may be that less carbon dioxide gets locked away in the ocean.

Andy Ridgwell, an environmental scientist from the University of East Anglia, has spent the past few years studying dust and says his work shows clearly the complexity of the system and the importance of not working uselessly with it without understanding the results. For this reason the need is to focus on cutting carbon dioxide giving off rather than dealing with the land surface aimlessly.

An American scientist, Robert Jackson, has shown that when native grassland areas are occupied by trees, carbon is lost from the soil. "We are studying why the soil carbon disappears, but one theory is that trees do a lot more of their growing above ground compared to grasses, so less carbon goes directly into the soil from trees. " said Jackson.

In wet areas of the world, the gain from trees absorbing carbon dioxide above ground seems to be outweighed by the loss of carbon from the soil below ground.

Countries that plan to combat global warming by planting trees may have to think again. Solutions to environmental problems are often more complex than they first appear, and understanding the Earth's climate is a very great challenge.

64. People usually hold the opinion that _______.

A. huge dust storms can destroy carbon dioxide

B. huge dust storms can destroy the oceans on the earth

C. planting trees could reduce global warming

D. planting trees is the only way to control huge dust storms

65. Andy Ridgwell, the environmental scientist, believes that _______.

A. environmental problems are more complex than expected

B. trees shouldn't have been planted in dry places

C. dust plays a more important part than trees

D. carbon dioxide is harmful to everything

66. Robert Jackson's experiment proves that _______.

A. carbon can turn grass into dust

B. trees hold more carbon than grass

C. less carbon can make trees grow faster

D. grassland areas should be covered by forests

67. The underlined word "combat" in the last paragraph means _______.

A. learn about        B. give up             C. live with        D. fight against

Martha was busy with her job. She believed she had to work harder because she loved her father who was sick with cancer. She had to provide for his expensive medicines. Her brothers and sisters meanwhile stayed with their father most of the time. They bathed him, sang for him, spoon-fed(用匙喂) him or simply kept him company.

One day Martha was hurt. She overheard(无意中听到) her father telling her mother, "All our children love me except Martha."

 "How can this be?" Martha thought. "Am I not the one killing myself in my work to have money to pay for his medicines? My brothers and sisters do not even provide their share in the expenses."

One night, as Martha was as usual late in going home, she saw her father was lying awake. She walked close to his bedsides. Her father held her hands and said, "I miss you. I don't have much time. Stay with me." And she stayed with her father holding his hand the whole night.

The next morning Martha said to everybody, "I have taken a leave of absence. I would like to be with father. I will bathe him and sing for him from now on." Her father had a beautiful smile. He knew Martha loved him, too.

     As children, we need the presence of our loved ones. Adults need no less. I have observed my mother’s orchids(兰花). When she is away for a long time, they are unhealthy and many of them wither(干枯). But when she is around , they bloom with beautiful flowers. My mother does nothing special . She just spends her time looking after them.

Before Martha heard her parents’ talk ,she thought her father _____.

  A. was satisfied with her love for him

  B. disliked her brothers and sisters

  C.was proud of her

  D. would recover from the disease

After staying with her father for one night, Martha _____.

  A.decided to give up her job

  B.understood what her father really needed

  C.realized her father loved her most

  D. loved her father more than before

By telling Matha’s story, what does the author try to express?

A.Nothing is more important than the company of loved ones.

 B. Money and a successful career don’t always bring happiness

C.Adults need the presence of their loved ones more than children do.

D.Plants like orchids do have feelings.

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