问题 问答题 简答题

化学耗氧量的意义是什么?

答案

参考答案:

化学耗氧量简称COD,表示用化学氧化剂(重铬酸钾、高锰酸钾)氧化废水中可氧化的污染物(有机物、亚硝酸盐、亚铁盐、硫化物)的过程中所消耗的氧。

COD越高说明水被污染的越严重,是表明水污染程度的重要综合指标,单位mg/l或ppm。

阅读理解

If you are living in the city, have you ever thought of going to live in the country for a change? Many people want to move from the country to the city because they think life in the city is more exciting and better than that in rural (农村的) areas, especially young people who like new and modern things.

Often people feel that they can find the latest styles only in the city. Other people are interested in technological (科技的) things and high-tech jobs and think they can find them only in a big city. If they want to find a job, especially a good position in a company, they feel they have to live in a city. To get these jobs, they are willing to put up with many of the disadvantages (不利因素) of city life such as heavy traffic and pollution.

However, it is now possible to enjoy a higher quality of life in the countryside and still enjoy some of the advantages (好处) of living in the city.

Nowadays, travel is fast and information is available (可获得的) on the Internet, so many people are able to do their work in home offices.

Because they have e-mail and personal computers, they don't have to be in big cities to do their business. It is not important where they actually work because the results of their work can be sent everywhere with technology. Now they can enjoy life in the countryside and still be able to do good business and successful careers.

小题1:The underlined phrase “put up with” (in Para. 3) probably means “_____”.

A.change

B.stand

C.be angry with

D.be pleased with小题2:Now people can enjoy life in the countryside and still be able to do good business and successful careers _____.

A.because of the Internet and fast travel

B.because of e-mail and personal computers

C.because travel is fast

D.because the rural areas are developing faster than cities小题3:What is the author's opinion?

A.She / he prefers to live in the countryside rather than live in the city.

B.She / he prefers to live in the city rather than live in the countryside.

C.She / he likes both city life and countryside life.

D.It is not clear which life she / he prefers.小题4:What would be the best title for this passage?

A.Life in the city

B.Life in the country

C.Go and live in the city

D.Go and live in the country

选择题