题目内容：

The largest land animal remaining on the earth, the African elephant is of much importance to African ecosystem. Unlike other animals, the African elephant is to a great extent the builder of its environment. As a giant plant-eater, it significantly shapes the forest-and-savanna(大草原) surroundings in which it lives, therefore deciding the conditions of existence for millions of other animals that live in its habitat.

It is the elephant’s great desire for food that makes it both 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 under-bushes, as well as pulls branches off big trees. This results in numerous open spaces in not only deep tropical forests but also the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth, which 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 create open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large-hoofed plant-eat-ers to move around and for small-sized plant-eaters to obtain their food as well.

Scientists are worried now that the African elephant has become an endangered species. If the elephant dies out, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

1. It can be inferred from the passage that the African elephant      .

A. is now the largest animal on the earth

B. determines life and death of millions of other animals in its habitat

C. has far-reaching impact on its habitat as a giant animal-eater

D. makes great contributions to its environment like other animals

2.The African elephant influences the ecosystem in the following ways except that     .

A. it creates open areas in deep tropical forests as well as woodlands

B. it pulls off the branches and leaves, shutting out the sunshine

C. its eating habit can be made use of by large-hoofed and small-sized animals

D. it encourages some kinds of plants growing in an indirect way

3.According to the passage, which of the following statements is true?

A. Numerous grown plants are the favorites of plant-eaters.

B. The extinction of the African elephant has nothing to do with the ecosystem.

C. Quantities of plants are consumed by African elephants, including branches and under-bushes.

D. The forest floor in rain forests is scarcely dotted with new shoots.

4.The passage is developed mainly by        .

A. presenting the changes in time order

B. making comparisons and giving examples

C. classifying similarities and differences

D. showing the effect and then explaining the reasons