问题 问答题 论述题

土壤有机质在土壤肥力中的作用。

答案

参考答案:

(1)土壤有机质是植物养料的重要来源为植物提供碳、氢、氧、磷、硫、钾、钙等以及多种微量元素。

(2)土壤有机质能提高土壤的蓄水、保肥和缓冲能力

(3)土壤有机质能改善土壤的物理性质,如使土粒形成良好的团粒结构;加深土壤颜色,有利于保温等。

(4)土壤有机质能促进土壤微生物的活动。

(5)土壤有机质是植物生长激素

阅读理解

Bicycles are very popular in China. In our country you can see bicycles almost everywhere. When you walk on the road, you will find a lot of people riding bicycles to schools, shops and anywhere else. Therefore, China is known as “the kingdom of bicycles”. In China, many families have one or two bicycles.

Compared with cars, bicycles have many advantages. First, they are much cheaper than cars. Most Chinese can’t afford cars, but they can afford bicycles. Second, bicycles are small enough to park anywhere, while cars need a larger piece of land to park. What’s more, with lower speed, bicycles are safer than cars.

However, bicycles also bring some problems. Some riders don’t obey the traffic rules and some riders don’t think about others safety. So they ride too fast. During the rush hour, too many bicycles may cause traffic accidents. We still have a long way to solve the problem.

小题1: Where can you see bicycles in China?

A.In the big city

B.In the town

C.Almost everywhere

D.In the countryside小题2:“The kingdom of bicycles” here is saying    .

A.China has plenty of bicycles

B.China makes bicycles

C.Only China has bicycles

D.All the Chinese have bicycles小题3: Which of the following is NOT an advantage of bicycles

A.Bicycles are much cheaper than cars.

B.Bicycles are more beautiful than cars

C.Bicycles are easy to park

D.Bicycles are safer than cars.小题4: What does the last sentence mean?

A.We should drive cars instead of riding bicycles

B.It’s too far to ride bicycles

C.We still need to do much to solve the problem

D.we should walk farther to solve the problem

单项选择题