45. On a rainy day the water running down the slopes of a hill is muddy because ________.

A. there is no terrace on the slopes　　　　　　 B. there is no small plant on the slopes

C. it washes away soil from the slopes　　　　　 D. there is too much soil on the slopes

44. What do you think of Iris?

A. Brave.　　　 　　 B. Kind.　　　 　　　 C. Honest. 　　　 D. Too careful.

B

On a rainy day, you will see many streams of muddy(多泥的)water running down the slopes(山坡)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 of the water. Most of the soil in the water is left behind on the terraces.

There are some other ways of soil conservation.

43. Which of the following is NOT mentioned in Iris’ worries?

A. Her electric cooker.　 　　　 B. Her baby.　　 C. Her key.　　 D. Her train.

42. Iris goes back to the kitchen to ________.

A. make sure that the cooker is off　　　　 B. turn off the cooker

C. feel the knob on the TV set　　　　　　 D. talk to someone

41. Iris worries too much because ________.

A. she usually forgets to turn off the cooker　　　 B. she usually forgets to turn off the TV set

C. she is very forgetful　　　　　　　　　　　 D. she usually forgets her key

39. A. jumped up 　　B. sat up　　　　　 　　C. rang up　　 　　　　D. knocked down

38. A. called　　　　　 　 B. told　　　 　　　　　　 C. encouraged 　　 　　 D. frightened

37. A. world　 　　　 B. country 　 　　　　　C. planet 　　 　　　　D. satellite

36. A. neighbour　 　　B. imagination　　　　 C. brother　 　　　　　　D. dog