题目内容：

    What happens inside the head of a soccer player who  repeatedly heads a soccer  ball  That question motivated a study of the brains of experienced players．

Researchers at the Albert Einstein College of Medicine in New York selected 34 adults ， men and women． All of the volunteers had played soccer since childhood and  now competed year﹣round  in adult soccer leagues． Each filled out a detailed questionnaire developed especially for this study to determine how many times they had headed a soccer ball in the previous year ， as well as whether they had experienced any known concussions  in the past．

Then the players completed computerized tests of their memory and other learning skills and had their brains scanned， using a complex new  M．R．I． technique which can find structural changes in the brain that can 't be seen during most scans．

According to the data they presented ， the researchers found that the  players who had headed the ball more than about 1 ， 100 times in the previous 12 months showed significant loss of white matter in parts of their brains involved with memory ， attention and the processing of visual information ， compared with players who had headed the ball less．

This pattern of white matter loss is " similar to those seen in traumatic brain injury" ，like that after a serious concussion， the researchers reported ，even though only one of these players was reported to have ever experienced a concussion．

The players who had headed the ball about 1 ， 100 times or more in the past year were also generally worse at remembering lists of words read to them ， forgetting the words far more often than players who had headed the ball less．

1.What type of writing is the texts　   　．

A. A medicine guide．

B. A book review．

C. A research report．

D. A sports advertisement．

2.What do we know about the volunteers　   　．

A. They had serious injury on the head．

B. They were adults who still played soccer．

C. They were all researchers about soccer．

D. They all had children who played soccer．

3.What was used to find the structural changes in the brains　   　．

A. Advanced computers．

B. A new technique M．R．I．

C. Special questionnaires．

D. Learning skills．

4.We can infer from the passage that　   　．

A. heading the ball is so harmful that it should be banned

B. heading the ball has advantages and disvantages as well

C. players heading the ball more than 1 ，100 times may suffer poor eyesight

D. heading the ball may influence the functioning of player's brain