题目内容：

Every hour spent in watching TV, DVDs and videos as an adult reduces life expectancy by almost 22 minutes, a study suggests. And viewing TV for an average of six hours a day can cut short your life by five years.

The research claims that a sedentary(久坐的) lifestyle is as bad for health as smoking and obesity, because of the dangers caused by inactivity and the greater opportunities it offers for unhealthy eating.

The academics conducting the study set out to calculate the overall risk to life expectancy from watching television. Their research involved more than 11,000 people over the age of 25.

Writing in the British Journal of Sports Medicine, they concluded. "TV viewing time may be associated with a loss of life, which is similar to other major chronic disease risk factors such as physical inactivity and obesity."

The researchers, from the University of Queensland, used information from the Australian Diabetes, Obesity and Lifestyle Study, together with population and death rate data.

But they said: "Although we used Australian data, the effects in other industrialized and developing countries are likely to be similar, considering the large amounts of time spent watching TV and similarities in disease patterns." In the United Kingdom, the average amount of time spent watching TV is four hours a day, compared with five hours in the United States.

Earlier this year, a separate study suggested the risk of developing type 2 diabetes and heart disease, or dying early, rises by as much as 20 percent after just two hours a day in front of the box.

England's Chief Medical Officer, Sally Davies, said: "Physical activity offers huge benefits and these studies back what we already know - that a sedentary lifestyle carries additional risks. We hope these studies will help more people realize that there are many ways to get exercise."

1.We can learn from the passage that_______

A．whether you watch TV or not has nothing to do with how long you will live

B．if an adult watches TV for six hours every day, he will die five years earlier

C．physical inactivity and obesity won't shorten your life

D．a sedentary lifestyle offers huge benefits.

2.The word "it" in the second paragraph refers to

A．a sedentary lifestyle

B．eating

C．smoking

D．obesity

3.What do we know from the last three paragraphs?

A．People in the United Kingdom watch TV longer than those in the United States.

B．That a sedentary lifestyle carries additional risks isn't supported by other studies.

C．Watching TV for two hours a day will increase the risk of illnesses or dying early by 20%.

D．It is through these studies that we know a sedentary lifestyle carries additional risks.

4.The passage is intended to _______.

A．inform the readers of a research on watching TV

B．warn the readers of the harm of watching TV and hope they do sports

C．tell the readers watching TV is also a good way to relax

D．tell the readers large amounts of people often watch TV