A、 Why certain people are aging sooner than others.
B、 How to make people live longer.
C、 The size of certain people"s brains.
D、 Which people are most intelligent.

【正确答案】 B

【答案解析】解析：从“Professor Taiju Matsuzawa wanted to find out how the process of aging could be slowed down．”可知研究的方向与长寿有关。

A、 A survey of farmers in northern Japan.
B、 Tests performed on a thousand old people.
C、 The study of brain volumes of different people.
D、 The latest development of computer technology.

【正确答案】 C

【答案解析】解析：从“he set about measuring brain volumes of a thousand people of different ages and varying occupations．”司推知。

A、 Our brains shrink as we grow older.
B、 Sixty-year-olds have better brains than thirty-year-olds.
C、 The front section of the brain does not shrink.
D、 Some people"s brains have contracted more than other people"s.

【正确答案】 D

【答案解析】解析：文中提到大脑萎缩的情况因人而异，可知D符合文意。

A、 Thinking can prevent the brain from shrinking.
B、 Blood circulation can prevent the brain from shrinking.
C、 Conversation can prevent the brain from shrinking.
D、 The fresh oxygen can prevent the brain from shrinking.

【正确答案】 A

【答案解析】解析：从“Matsuzawa’s findings show that thinking can prevent the brain from shrinking．”可知思考可以延缓大脑萎缩。

A、 Lawyers.
B、 Clerks.
C、 Farmers.
D、 Shop assistants.

【正确答案】 A

【答案解析】解析：从“Those least at risk are lawyers，followed by university professors and doctors．”可知答案为A。