题目内容：

    It is very common that many students complain they lack concentration. For example ,“I can’t concentrate.” “My mind wanders when I try to study.”

We all have the ability to concentrate. Think of the times when you were attracted to a super novel or the times when you were playing your guitar or piano. But at other times your mind races from one thing to another. Here are some tips.

Rest from time to time. Remember to take short breaks. Lectures are usually 50 minutes long, and that’s about the length of time most people can direct their attention to one task. But that’s just an average. Your concentration time might be shorter (20-35 minutes) or longer (perhaps 90 minutes). When you take a break, you get more oxygen to your brain! When we sit for long periods, blood tends to be pooled in our lower body and legs. Get up and walk around the room for a couple of minutes. As a result, more oxygen is carried to the brain and you can concentrate better.

If you study one subject for a long time, you may find it hard to concentrate. Many students improve their concentration by changing one subject to another every one to two hours. In this way you can pay more attention to something that’s different.

Reward yourself. Give yourself a reward when you’ve completed a task. The task might be small, such as staying with a difficult paper until you’ve finished. But giving yourself a reward can help you be more interested in doing other tasks.

Increase your activity level. Your concentration wanders more easily if you just read an article straight through. Instead, take the heading for each part and turn it into a question. For this part, that would be, “How can I increase my activity level while studying?” Then study that part to answer that question. Do this routinely. The questions give us a focus for each part and increase our involvement (参与).

1.According to Paragraph 3, what’s the purpose of walking around?

A.To help us stay fit.

B.To provide the brain with more oxygen

C.To benefit our lower body.

D.To increase our concentration time to 90 minutes.

2.What’s the best title for Paragraph 4?

A.Study for one hour each time.

B.Do something difficult.

C.Change subjects.

D.Study in different ways.

3.In the last paragraph, the writer suggests that______.

A.we just read the heading of some articles

B.we do our best to read an article straight through

C.we ask other people questions about the article we are reading

D.we ask ourselves questions about what we are reading

4.The writer wrote the passage to______.

A.encourage us to try to concentrate

B.give us the reasons for a lack of concentration

C.teach us how to concentrate while studying

D.list the benefits we can get from concentration