A latest national survey has found that over half of China's netizens are suffering from various mental problems although some 62 percent of them claim at the same time that they are happy on the whole anyway.
This is the result of China's first White Paper on Netizens' Health Conditions issued on Wednesday by 39.net, China's largest authoritative website on health sciences. It is the first most comprehensive health survey on netizens' health situation ever conducted in China in ten years' time. The white paper came out after two months of online and offline research that involved over 150 thousand netizens, covering topics and questions on health knowledge, mental situation, sense of health, and living habits.
According to the white paper, more than 70 percent of China's netizens say they are suffering from mental problems such as bad memory, anxiety, depression, and a lack of confidence. And a similar 72 percent of them also say they are often suffering from diseases like insomnia, dizziness, joint degeneration and achings. Meanwhile, another 53 percent of netizens believe that white collar employees who have bigger work pressures are more likely to catch mental problems.
The white paper adds, doing almost no sports and spending long time surfing online lead to the above mentioned health problems among netizens. Only 9 percent of netizens take up sports on weekends while over 40 percent stay home, surfing. And only 16 percent netizens can assure more than eight hours' sleeping daily.
At present, China has a netizen population of 162 million, with a monthly consumption of 186 yuan, or about 25 dollars, on Internet surfing.
The national survey on netizens' health situation ________.

A．was conducted by sohu.com	B．is conducted every year
C．was carried out online and offline	D．covered about half a million netizens

. Which of the following has the closest meaning to the underlined part "white collar"?

A．White clothes.

B．White offices.

C．Office workers.

D．White people.

. All the following factors have been mentioned to cause the health problems among netizens EXCEPT ________.

A．doing no sports	B．spending long time online
C．heavy work pressures	D．shopping online

.What’s the main idea of the passage?

A．China has a large netizen population.

B．Many netizens in China have mental problems.

C．The Internet has a negative influence on people.

D．How to surf the Internet safely and healthily.