题目内容：

Office workers should know that long periods of sitting at your desk may be a killer. Scientists have shown a new threat from this lifestyle that they call  “muscular inactivity (肌肉迟钝)”．

Sitting still for long periods of time leads to the buildup of substances (物质) in the blood that are harmful to health. And exercise alone won’t drive them away.

Millions of people spend their days between car，office desk and the sofa in front of the TV. While the bad influences are well rocognized，it has been thought that they can be changed by regular trips to the gym or swimming pool.

Now researchers say that is not enough. In addition to regular exercise，office workers need to keep moving while they work，by making regular trips to the printer，coffee machine or to chat with workmates.

Elin Ekblom­Bak，an expert on health，says research shows long periods of sitting and lack (缺乏)  of “whole body muscular movement”  are strongly linked to obesity，heart disease and cancer，and a higher risk of death，regardless of (不管) whether they take enough exercise.

“Everyone knows about the health benefits of regular exercise. But what we haven’t realized before is that long­period sitting down carries an extra risk that cannot be dealt with by taking exercise，” Dr Ekblom­Bak said，adding that sitting still should be recognized as a risk to health.

“It is important to have a five­minute break from desk work every 45 minutes. Don’t email workmates—walk across the office to give them the message. Take a coffee break or put the printer in the next room. I am a desk worker and I try to do it. It is not difficult but sometimes you get lost in your work and you forget about it.”

However，more studies are needed to confirm the ill effects of sitting for too long and ways of fighting them. But at present they conclude that  “keep moving”  should be added to the advice to “keep exercising.”

1.Nowadays，many office workers wrongly think that________.

A．long periods of sitting has bad influences on them

B．regular exercise benefits them after long periods of sitting

C．they are living a lifestyle called “muscular inactivity”

D．it’s unfair for them to sit in the office for too long

2.What does the author suggest office workers should do?

A．Chat with workmates often.

B．Send emails instead of chatting.

C．Keep moving in the office regularly.

D．Take more exercise after work.

3.The last paragraph suggests that the result of the study is________.

A．scientific

B．uncertain

C．unbelievable

D．convincing

4.What would be the best title for the passage?

A．A new threat ：long­period sitting

B．Office workers should keep exercising

C．Taking exercise benefits a lot

D．Keep moving，it could save your life