Question

At first, the earth’s surface(表面) layer (层) was made up of huge blocks of hard, solid rocks. Then slowly, the rocks broke up into smaller and smaller pieces. Finally stones, pebbles (卵石) and grains of sand were formed. Many sorts of plants and animals lived and died on the surface of the earth. Their remains mixed up with the stones, pebbles and formed soil. The outmost layer of the earth is soil.

There are many ways in which large pieces of rock break into smaller ones. Wind, water, heat and cold help to break up rocks. When winds blow grains of sand against a large rock for a long time, the softer layers of the rock are slowly worn away. These leave holes and cracks (裂缝) in the rock, which become bigger and finally the rock breaks up into smaller pieces.

The moving water of streams and rivers also helps to break up rocks. As the water moves along, it carries with it small pieces of rock. These rub the larger ones. Thus, the larger rocks are worn down to smaller pieces.

The heat of the sun is also helpful to breaking up rocks. When the sun shines, the rocks become very hot. If these rocks are suddenly cooled, they may crack. Ice also plays a part in making soil. Water in the cracks can turn into ice in cold weather. As this happens, it becomes bigger and the cracks become wider, and finally break into smaller pieces.

1.According to the passage, soil ________.

A. forms very slowly

B. is a mixture of stones, pebbles and sand

C. makes up the layers of the earth

D. is becoming smaller and smaller

2.How many factors are mentioned in helping break up rocks?

A. Three.B. Four.C. Five.D. More than five.

3.Which of the following speeds up(加速) the breaks of rocks most?

A. Hot weather.

B. Cold water.

C. Sharp changes in temperature.

D. More dead plants in the cracks.

4.Which of the following is NOT true?

A. The remains of many plants and animals formed soil.

B. If a large rock never moves, it will never break up.

C. Even if a large rock never moves, it will break up.

D. Ice in the cracks helps to break up rocks.

Answer

1.A

2.B

3.C

4.B

【解析】

试题分析: 文章叙述的是岩石形成土壤的过程，以及影响岩石碎裂的因素。

1.A 推理判断题。根据第一段的描述，尤其是“Then slowly…”可知，土壤的形成是一个非常缓慢的过程。故选A。

2.B 细节理解题。根据第二段中Wind, water, heat and cold help to break up rocks.以及二、三、四段的内容可知，文章叙述了风、水、热、冷对岩石碎裂的影响。故选B。

3.C 推理判断题。根据最后一段中As this happens, it becomes bigger and the cracks become wider, and finally break into smaller pieces.可知，温度的急剧变化会加速岩石的碎裂。故选C。

4.B 推理判断题。根据文章内容可知，巨大的岩石碎裂成小块岩石的方式很多，风、水、热、冷等都是其中的因素，由此可推断B项内容错误。故选B。

考点：考查科普类阅读。