To prevent this we must put basic substances back. One way of doing this is putting
manure (肥料)on the soil.This contains the remains of plants that have been eaten, and,
if we add it to the soil, we are returning some of the basic substances. In Europe and in
Japan,manure from animals has for long been used in this way. Unfortunately much of the
animal waste in India is used as fuel because there is not enough wood to burn. This means
there is less manure for the crops. Even when we use manure, we cannot put back into the
soil more of the basic substances than have been taken out. Often the soil does not have
enough of them in the first place,and so we must provide extra supplies.We can use chemical
fertilizers).
Experiments in India have shown that,if we use a fertilizer containing a mixture of
nitrogen and phosphorus, we get half as much rice again from the crops on any one piece
of land.
60. According to the passage, how many methods are introduced to improve the soil?
A. One. B. Two. C. Three. D. Four.
61. The underlined word “this”( in Paragraph 4) refers to the fact that _____.
A. the soil would become too poor for plants to grow in it at all
B. we are taking some substances away from the soil
C. the plant takes up these essential substances from the soil
D. even today many people in the world go hungry
62. To make sure that the soil has enough basic substances, people can _____.
A. remove plants from the soil B. provide the soil with extra supplies
C. plant as many plants as possible D. stop planting in the soil
63. The passage is mainly about _____.
A. why more food is needed
B. how to grow better crops
C. the fact that people have not always enough to eat
D. the essential substances that plants need
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