题目内容：

Sometimes there doesn’t seem to be enough rain. Other times there is too much. Maybe thereisn’t a lot we can do to control the rain, but there is a lot we can do to reduce problems caused bydifferent rainfall patterns.

A new development at the London Wetland Centre in Barnes solves the problems of managingwater with a “Rain Garden”. We are likely to be hearing about it a lot more often over the next fewyears. The idea is that the garden owner can store rainwater and use it in dry periods. They canreduce the problems caused by extra rain this way.

One of the key problems that the rain garden tries to deal with is the problem caused by toomuch water in the street. In a natural environment, a lot of rainwater is sent back into the air byplants. Much is also absorbed deep into the ground, and flows into streams and rivers. What happensin city environments can be completely different —— a large amount of rainwater flows straight offthe hard surfaces of roofs and roads. The harder the rain, the less likely it will be absorbed into theground —— floods are the result. Rainwater running off roads is often polluted.

The rain garden deals with living plants rather than hard surfaces. Plants are designed to holdwater and release it slowly, either into the ground, to be absorbed by plant roots (and so eventuallyback up into the atmosphere) or to go down into the water table. Not only does the rain gardenreduce the amount of water that flows onto the street, but it helps to clean it because plants are very goodat breaking down pollutants(污染物).

1.What’s the main idea of the first paragraph?

A．Explaining why there is a lack of rain at times.

B．Introducing several different patterns of rainfall.

C．Telling us how to avoid problems caused by rain.

D．Giving the idea that there are ways to manage rain water.

2.According to the second paragraph, “Rain Gardens" are likely to _____.

A．harm the environment in the short run

B．become popular over the next few years

C．be turned down by most new developments

D．be too expensive for common people to accept

3.We can learn from the third paragraph that _____.

A．floods are often the results of small rains

B．a heavy rain is less difficult for plants to absorb

C．the rain garden helps send rainwater back into the air

D．larger amounts of rainwater flow straight off in city environments

4.According to the last paragraph, what does the rain garden help to clean?

A．The plants         B．The ground.        C．The water.         D．The street.