[专升本类试卷]专升本英语(阅读)模拟试卷5.doc

[专升本类试卷]专升本英语（阅读）模拟试卷5

一、Part III Reading Comprehension

Directions: In this part there are four passages. Each passage is followed by a number of comprehension questions. Read the passages and choose the best answer to each question. Then, mark your answer by blackening the corresponding letter on the Answer Sheet.

0 On a rainy day, you will see many streams of muddy(多泥的)water running down the slopes(斜坡)of a hill. The water is muddy because it washes away soil from the hill slopes.

Sometimes soil is blown away by strong winds. When the soil is carried away by water or wind, we say that the land is eroded(侵蚀). This is known as soil erosion.

Plants cannot grow on eroded land. There is not enough soil on eroded land to give them the things they need. Plants need water and salts from the soil.

We can do a number of things to stop soil erosion. This is called soil conservation(保护).

One way of soil conservation on flat, open ground is to grow small plants such as grasses. Their roots hold the soil tightly together.

Another way is to plant trees around an open field. Thus soil erosion by strong winds cannot take place. Rows of trees act as a very big wall.

Soil erosion on slopes can be stopped by cutting "steps" called terraces(梯田). Water carrying soil cannot run straight down the slope now. It has to run down the terraces. This slows down the flow(流速)of the water. Most of the soil in the water is left behind on the terraces.

There are some other ways for soil conservation.

1 On a rainy day the water running down the slopes of a hill is muddy because______ . （A）there are no terraces on the slopes

（B）there are no small plants on the slopes

（C）it washes away soil from the slopes

（D）there is too much soil on the slopes

2 Plants cannot grow on eroded land because______.

（A）there is a lot of sand in it

（B）there is not enough water and salts in it

（C）there is no water in it

（D）the land is too hard

3 The way of soil conservation on flat, open ground is______. （A）to grow small plants such as grasses

（B）to plant trees around an open field

（C）to add fertilizer to the soil

（D）A and B

4 Cutting "steps" called terraces on slopes______.

（A）can slow down the flow of the water

（B）helps plants grow better

（C）prevents the soil being carried away by winds

（D）makes the plants' roots hold the soil together

4 Bacteria(细菌)are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter; a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus, if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile(1.

6 kilometers)tall.

Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy-looking "hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some little-understood mechanism.

From the bacterial point of view the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses(糖蜜)is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope even those with no flagella often bounce about in the water. This is because they collide with the water molecules and are pushed this way and that molecules move so rapidly that within a tenth of a second the molecules around a flagellum have been replaced by new ones. Even bacteria without flagella are thus constantly exposed to a changing environment.

5 Which of the following is the smallest?

（A）A pinhead.

（B）A rounded bacterium.

（C）A microscope.

（D）A rod-shaped bacterium.

6 According to the passage, someone who examines bacteria using only a microscope that magnifies 100 times would see______.