services to be performed are interpreted as contracts in courts. Sales and

C

LONDON: What could possibly be wrong with planting trees？ The benefits are obvious; they firm the soil, soak up (摄取) extra water and take carbon dioxide (二氧化碳) our 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 soaking up 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. The dust fuels oceanic life.

Dust from China is carried east and left in the Pacific Ocean. If a tree-planting programme there is successful and the dust supply reduced, the net 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 that the complexity of the system and the importance of not tinkering(粗劣地修补) with it without understanding the results. For this reason the need is to focus(集中) on cutting carbon dioxide giving off rather than monkeying (瞎弄) about with the land surface.”

An American scientist, Robert Jackson, has shown that when native grassland areas are invaded(侵入) 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, ” says Jackson.

In wet areas of the world, the gain from trees absorbing carbon dioxide above ground seems to be outweighed(超过) 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.

63．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．huge dust storms can’t do anything beneficial for man

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

64．Andy Ridgwell, the environmental scientist, believes that      .

A．dust plays a more important part than trees

B．trees should’t have been planted in dry places

C．carbon dioxide is harmful to everything on the earth

D．environmental problems are more complex than expected

65．Robert Jackson’s experiment proves that        .

A．grassland areas should be covered by forests

B．trees hold more carbon than grasses

C．carbon can turn grass into dust

D．less carbon can make trees grow faster

66．The underlined word “combat” in the last paragraph means     .

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

[    ]

A. peculiar

B. particular

C. special

D. characteristic

still don't understand, according to a British study presented (递交) last week to an international conference

(大会) on smoking.

Anti-smoking activists at the second "Tobacco or Health" conference pointed out that although adults

were giving up smoking in growing numbers, more and more young people were taking up the habit,

particularly girls.

One-fourth of the 15-year-old young people smoke regularly, according to the study made in 27 countries

by Edinburgh University together with the World Health Organization.

In Western Europe, girls were more likely to smoke than boys. In Germany or in England, one third of

the girls were smokers compared to (相比) one in four boys. In Eastern Europe, the girls "still fall behind"

those in the Western Europe but were "catching up" quickly, said the study.

The study dealt with the behavior of 15-year-old in seven European countries between 1986 and 1998.

The percentages (百分比) of young women smoking went from 17% to 36% in Austria, from 17% to

28% in Norway, from 21% to 28% in Hungary.

In the seven countries and regions studied-Austria, Finland, Hungary, Norway, Sweden, Switzerland and

Wales-more girls smoked than boys, with the exception (例外) of Hungary.

[    ]

B. boys

C. girls

D. old men

[    ]

B. as large as

C. smaller than

D. as small as

[    ]

B. the World Health Organization

C. "Tobacco or Health" conference

D. Edinburgh University and the World Health Organization

[    ]

B. Austria

C. Hungary

D. Sweden

[    ]

B. report something interesting happened in England

C. describe the present condition of European smokers

D. warn young people around the world against smoking