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It is said that farmers or peasants, especially those in developing countries, are often criticized for cutting down forests. But a new study suggests that many farmers recognize the value of keeping trees.

Researchers using satellite images found at least ten percent trees cover on more than one billion hectares of farmland. 1 . Earlier estimates were much lower but incomplete. The authors of the new study say it may still underestimate the true extent worldwide.

The study found the most trees cover in South America. 2 . North Africa and West Asia have the least.

The study found that climate conditions alone could not explain the amount of trees cover in different areas. 3 . There are areas with few trees but also few people, and areas with many trees and many people. The findings suggest that things like land rights, markets or government policies can influence tree planting and protection.

Dennis Garrity heads the World Agroforestry Center. 4 . The problem, he says, is that policy makers and planners have been slow to recognize this and to support such efforts.

The satellite images may not show what the farmers are using the trees for, but trees provide nuts, fruit, wood and other products. 5 . Even under drought (¸Éºµ) conditions, trees can often provide food and a way to earn money until the next growing season.

Some trees act as natural fertilizers. They take nitrogen (µªÆø) out of the air and put it in the soil. Scientists at the Center say the use of fertilizer trees can reduce the need for chemical nitrogen by up to three-fourths. Trees also capture carbon dioxide, a gas linked to climate change.

A. Nor could the size of nearby populations, meaning people and trees can live together.

B. He says farmers are acting on their own to protect and plant trees.

C. Almost all of it is covered by trees.

D. They also help prevent soil loss and protect water supplies.

E. He devotes most of his time to making people realize its importance.

F. That is nearly half of the farmland in the world.

G. Next comes Africa south of the Sahara, followed by Southeast Asia.

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Culture means any human behavior that is learned in human society. All of the meaningful parts of a culture are passed on to different generations through tradition or social learning. 1 Culture exists in agricultural as well as industrialized (¹¤Òµ»¯µÄ) societies.

Culture is necessary for the survival (ÐÒ´æ) of human beings. Practically everything humans know, think, value, feel, and do is learned through taking part in a cultural system. 2 Here is one of the cases of children growing up apart from human society. In the province of Midnapore in India, a scientist was told by local villagers that there were ¡°ghost (¹í)¡± in the forest. Upon looking into the case, he found that two children appeared to have been living with a group of wolves in the forest. 3 In his diary, the scientist describes his first view of Kamala and Amala (the names of the children).

Kamala and Amala were terrible-looking creatures; the heads were like big balls covering the shoulders. Their eyes were bright and sharp, unlike human eyes. They were very fond of raw meat and raw milk. 4

It is important for children to live in a healthy cultural environment because they learn knowledge through imitating others. 5

A. From this viewpoint, all human groups have a culture.

B. These children were the ghosts described by the local people.

C. This statement is well supported by some well-written cases.

D. Human beings can develop abilities by fighting against nature.

E. Culture refers only to the art and classical music of a particular society.

F. In general, their behaviors and habits were totally different from human beings.

G. They learn human languages and behaviors by taking part in a certain cultural group.

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