搜题请搜索小程序“爱下问搜题”
问题 单项选择题

下列生态系统中，食物链结构最为单纯的是( )。

A．森林

B．草原

C．农田

D．海洋

答案

参考答案：C

解析： C项农田中的生物之间的关系是单纯的捕食与被捕食关系，其他选项所含生物种类多，关系也很复杂，故选C。

选择题

You'll have to book a ticket __________ if you want to see that show. [ ]

A. on time  

B. in advance

C. on schedule  

D. in time
查看答案
单项选择题

Do you think there is too much noise in our city If you live near an airport, you will be unhappy because a plane often makes a loud noise. The sound of planes or heavy vehicles is likely to cause deafness if heard continuously.
However, most people in our city do not seem to mind noise. They like to enjoy music when they are doing uninteresting jobs. It is a new danger because pop music, when played through powerful amplifiers, can reach 120 decibels at a distance of five feet. A continuous noise of over 85 decibels can cause deafness. It was discovered that many young people in America could hear no better than 65-year-old people.
In the past we used to think that only workers in very noisy places would become deaf. For example, when newspapers and books are being printed, the noise level is over 85 decibels, and some of the workers become deaf. Today, however, scientists believe that 10 percent of the workers in Britain are being deafened by the noise.
Sometimes noise of less than 85 decibels can make some people tired and stressed. We all know that too much noise makes life difficult and unpleasant. It can do great harm to people’s health and prevent people from working well. Workers in noisy offices are not as efficient as those in quiet offices. Noise makes people less efficient. Can anything be done to reduce or control noise
In Britain the government has made several laws to reduce noise. Though the government has spent a lot of money in making airports and main roads quieter, many people think that there are still not enough laws. For example, there are no laws to control the noise of machines. In Japan, America and Norway there are such laws. As a result, workers can be given compensation if they become deaf.

Who can be given compensation if they become deaf

A．American workers.

B．British workers.

C．Both American workers and British workers.

D．None of the above answers.
查看答案