70. The passage is developed mainly by.

A. showing the effect and then explaining the causes

B. pointing out similarities and differences

C. describing the changes in space order

D. giving examples

答案  67.C  68.D  69.D  70.A

Passage 44

(07·辽宁A篇)

What will people die of 100 years from now? If you think that is a simple question, you have not been paying attention to the revolution that is taking place in bio-technology(生物技术). With the help of new medicine, the human body will last a very long time. Death will come mainly fom accidents, murder and war. Today’s leading killers, such as heart disease, cancer, and aging itself, will become distant memories.

In discussion of technological changes, the Internet gets most of the attention these days. But the change in medicine can be the real technological event of our times. How long can humans live? Human brains were known to decide the final death. Cells(细胞) are the basic units of all living things, and until recently, scientists were sure that the life of cells could not go much beyond l20 years because the basic materials of cells, such as those of brain cells, would not last forever. But the upper limits will be broken by new medicine. Sometime between 2050 and 2100, medicine will have advanced to the point at which every 10 years or so, people will be able to take medicine to repair their organs ( The medicine, made up of the basic building materials of life, will build new brain cells, heart cells, and so on-in much the same way our bodies make new skin cells to take the place of old ones.

It is exciting to imaging that the advance in technology may be changing the most basic condition of human existence, but many technical problems still must be cleared up on the way to this wonderful future.

70. From the passage, we know the reason why around 10% of people are left-handed is that ________.

  A. their frontal lobe is usually dominant

  B. their temporal lobe is usually dominant

  C. their right brain is usually dominant

  D. their left brain is usually dominant

答案  68.B  69.A  70.C

Passage 43

(07·重庆D篇)

The African elephant, the largest land animal remaining on earth , is of great importance to African ecosystem(生态系统). Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the forest-and-savanna(大草原)surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat(栖息地).

It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and underbushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of

the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

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