题目内容：

Inner Mongolia Autonomous Region is an important ecological screen for the north of China and even the whole country. Building a green great wall to ensure China’s ecological security is one of the most important things of autonomous region.

The largest ecological function zone in the north of China, Inner Mongolia has a variety of landscapes, including forests, grasslands, wetlands, rivers and lakes. In recent years, the region’s environment has improved, with its forest and grassland area having increased and desert reduced.

However, it still faces a number of challenges in ecological preservation. For instance, the region faces severe water shortages with the number of lakes dropping from 427 in 1987 to 145 in 2010. In addition to a lack of rainfall, huge water consumption in agricultural and industrial production has worsened the water shortage. Too much use of fertilizers has damaged the soil and affected the growth of grass, accelerating the expansion of the desert, which results from a lack of water.

The local government encourages planting trees on grassland as they can get more pay for trees than by growing grass. However, the trees they plant often have a low survival rate as they have a high water consumption rate. Also, to treat wetlands, some areas have planted a large number of a single tree species. This practice may damage biodiversity (生物多样性) and endanger the survival of certain animals.

Experts suggest taking the region’s water resources and weather conditions into consideration in future ecological projects.

1.What do we know about the green great wall in Inner Mongolia Autonomous Region?

A. It adds the beautiful scenery to this area.

B. It acts as a guard to protect the north of China.

C. It works well in saving the endangered animals.

D. It contributes to the decrease of the grassland.

2.What does the third paragraph mainly talk about?

A. The causes of water shortages.    B. The protection of ecological environment.

C. The solutions to water shortages.    D. The importance of ecological environment.

3.What does the underlined word “accelerating” in Paragraph 4 probably mean?

A. weakening    B. shortening

C. lessening    D. quickening

4.What’s the author’s purpose of writing the text?

A. To tell the function of the green great wall.

B. To introduce the green great wall to the readers.

C. To provide guidance on traveling around Inner Mongolia.

D. To offer some advice on building the green great wall.