Question

Much of the water we use comes from snow. Melting snow provides water for rivers, electric power centers and agricultural crops. In the western United States, mountain snow provides up to 75% of all surface water supplies.

Snowfall helps to protect plants and some wild animals from cold, winter weather. Fresh snow is made largely of air trapped among the snow crystals. Because the air has trouble moving, the movement of heat is greatly reduced.

Snow also is known to influence the movement of sound waves. When there is fresh snow on the ground, the surface of the snow takes in, or absorbs, sound waves. However, snow can become hard and flat as it becomes older or if there have been strong winds. Then the snow's surface will help to send back sound waves. Under these conditions, sounds may seem clearer and travel farther.

Generally, the color of snow and ice appears white. This is because the light we see from the sun is white. Most natural materials take in some sunlight. This gives them their color. However, when light travels from air to snow, some light is sent back, or reflected. Snow crystals have many surfaces to reflect sunlight. Yet the snow does take in a little sunlight. It is this light that gives snow its white appearance.

Sometimes, snow or ice may appear to be blue. The blue light is the product of a long travel path through the snow or ice. In simple terms, think of snow or ice as a filter. A filter is designed to reject some substances, while permitting others to pass through. In the case of snow, all the light makes it through if the snow is only a centimeter thick. If it is a meter or more thick, however, blue light often can be seen.

1.How many functions of snow are discussed in the passage?

A．One             B．Two              C．Three            D．Four

2.Why does snowfall help to protect plants from cold?

A．Because snow crystals contain heat.

B．Because snow crystals have air in them.

C．Because snow crystals are easy to blow away.

D．Because snow crystals send out heat when melting.

3.It can be inferred that ______.

A．hard snow is better in protecting wild animals than fresh snow

B．fresh snow is better in sending sound waves than hard snow

C．fresh snow is better in taking in sound waves than hard snow

D．hard snow provides less water than fresh snow

4.The color of snow and ice appears white because snow crystals________.

A．send back none of the sunlight             B．send back all of the sunlight

C．take in most of the sunlight                D．take in some of the sunlight

 

Answer 1

【答案】

1.C

2.B

3.C

4.D

【解析】

試題分析：本文給我們介紹了我們常見的雪的作用，及雪為什么會成白色。這里提到的它的作用有三點，一是雪給我們提供水源。二是雪能夠給野生動植物防寒。三是雪能影響聲的傳播。

1.這是細節(jié)理解題。根據(jù)前三自然段可知雪能提供水源，能給野生動物和植物防寒，能影響聲的傳播，故選C。

2.這是細節(jié)理解題。根據(jù)Fresh snow is made largely of air trapped among the snow crystals. Because the air has trouble moving, the movement of heat is greatly reduced.因為雪里有空氣，阻止熱的運動。故選B。

3.這是推理判斷題。根據(jù)When there is fresh snow on the ground, the surface of the snow takes in, or absorbs, sound waves. However, snow can become hard and flat as it becomes older or if there have been strong winds. Then the snow's surface will help to send back sound waves. Under these conditions, sounds may seem clearer and travel farther.因為新鮮的雪能夠吸收聲波，這就影響了聲的速度，而硬的雪有利于聲的傳播，加快了聲的速度。故選C。

4.這是細節(jié)理解題。根據(jù)Snow crystals have many surfaces to reflect sunlight. Yet the snow does take in a little sunlight. It is this light that gives snow its white appearance.雪的晶體有許多表面來反射陽光，雪就吸收了一些光，就是這種光讓雪成白色。故選D。

考點：這是一篇科普性的文章。

點評：推理判斷就是根據(jù)作者的意圖和傾向來完成相關的問題。 根據(jù)你對文章的理解，來判斷各個選項的正誤。最重要的就是讀懂句子的意思，找出文章的中心，這種閱讀是深層閱讀，但是你最重要的就是找出文章的中心意思，抓住主要句子和相關句子的意思就可以解決了，要注意題目中的一些關鍵詞和文章中的句子的對比，尤其是一些轉折詞、連詞等等。