【题目】At first, the earth's surface layer (was made up of huge blocks of hard, solid rocks. Then slowly, the rocks broke up into smaller and smaller pieces. Finally stones, pebbles(砾石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 up 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 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 in 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 up into smaller pieces.

1 According to the passage, soil __________.

A. forms very slowly

B. is a mixture only of stones, pebbles and sand

C. makes up the layers of the earth

D. is becoming smaller and smaller

2 Which of the following speeds up the breaks of rocks most?

A. Hot weather.

B. Cold water.

C. Sharp changes in temperature.

D. More dead plants in the cracks.

3Which of the following is NOT true?

A. The remains of many plants and animals can form 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.

4 The best title for this passage should be __________

A. Soil from rock

B. Ways to break up rocks

C. Soil on the earth

D. Soil, outmost layer of the earth

 0  144801  144809  144815  144819  144825  144827  144831  144837  144839  144845  144851  144855  144857  144861  144867  144869  144875  144879  144881  144885  144887  144891  144893  144895  144896  144897  144899  144900  144901  144903  144905  144909  144911  144915  144917  144921  144927  144929  144935  144939  144941  144945  144951  144957  144959  144965  144969  144971  144977  144981  144987  144995  151629 

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网