阅读理解 If you dig down deep enough into the earth, you will find rock. Over the to

阅读理解

If you dig down deep enough into the earth, you will find rock. Over the top of most of this rock there is a layer of soil, like icing on a cake. You may call it earth or dirt, but the real name is soil.

The top layer of this soil is not very deep, but it is one of the most important things in the world. To grow well, plants need good topsoil. First, topsoil is made of little pieces of rock. Wind and sun, ice and water and plants have slowly broken big rocks up into little pieces. Then, these little pieces of rock have become mixed with many other bits of things：crumbled(粉碎的)pieces of dead plants and dried leaves, even dead insects and other dead animals. So the topsoil is bits of rock mixed with humus that used to be living things.

In some places earthworms are helpful in making good soil. As they crawl through the earth getting their food, they. make little tunnels that air and water come through. And they turn the soil over in such a way that rock pieces are slowly pushed to the top. Besides, earthworms grind up the soil as they eat.

If you put some soil in a glass of water, the rock, which is heavier, falls to the bottom of the glass. The humus, which is made of lighter things, floats on top.

1．The layer which spreads over most of the rock is called ________.

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A．topsoilB．soil or dirt or earthC．the icing of a cakeD．humus

2．Soil－making mainly depends on ________.

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A．earthwormsB．wind and sunC．ice, water and plantsD．both B and C

3．According to this passage, earthworms are helpful to the soil in ________ ways.

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A．fourB．fewC．twoD．three

4．Humus is made of ________ plants, leaves, insects, animals etc.

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A．livingB．deadC．growingD．dying

5．What will happen if you put a handful of topsoil in a glass of water?

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A．The humus comes above the rock bits.

B．The humus sinks down to the bottom.

C．The rock pieces float on the top.

D．The rock bits and the humus become mixed.

试题答案

答案：B;D;C;B;A

解析：

1．B由You may call it earth or dirt，but the real name is soil．得出正确答案。 2．D由Wind and sun，ice and water and plants have slowly broken big rocks up into little pieces．一句得出答案。 3．C由They make little tunnels that air and water come through．And they turn the soil over in such a way that rock pieces are slowly pushed to the top．Be sides，earthworms grind up the soil as they eat．推出答案。 4．B由第二段最后…these little pieces of rock have become mixed with many other bits of things：crumbled（粉碎的）pieces of dead plants and dried leaves ，even dead insects（昆虫） and other dead animals．So the topsoil is bits of rock mixed with humus that used to be living things．得出正确答案。特别要搞清Used to be living things是“曾经是活的东西”的含义。 5．A由最后一段中The humus，which is made of lighter things，floats on top．推出答案。