题目内容：

“A room without books is like a body without a soul,” observed the Roman philosopher, Cicero. It can also be a sign of financial problems to come. New research has uncovered a strong connection between the earning of adults and whether they grew up surrounded by books as children.

Three economists at the University of Padua—Giorgio Brunello, Guglielmo Weber and Christoph Weiss—studied 6000 men born in nine European countries and concluded that children with access to books could expect to earn more money than those who grew up with few or no books.

They studied the period from 1920 to 1956, when school reforms saw the minimum school leaving age raised across Europe. They booked at whether, at the age of 10, a child lived in a house with fewer than 10 books, a shelf of books, a bookcase with up to 100 books, two bookcases, or more than two bookcases.

Over the period studied, the research, published in The Economic Journal, found that an additional year of education increased a man’s average lifetime earnings by 9%. Men brought up in houses with less than a shelf of books earned only 5% more as a result of the extra year’s education, compared with 21% more for those who had access to a lot of books. And those who had access to books were more likely to move to the better-earning opportunities in cities than those without books. The men’s first job was also much more likely to be a white-collar job.

The economists offer a number of theories for the results. “Perhaps books matter because they encourage children to read more and reading can have positive effects on school performance,” they said.

The number of books in children’s homes can effectively predict their cognitive(认知的) test scores. This may indicate a home that encourages cognitive skills, which are important for economic success in life.

1.Why did author mention Cicero’s words in the first paragraph?

A. To make an argument.    B. To introduce the topic.

C. To express his own views.    D. To arouse readers’ interest.

2.What can we learn about the people studied by the researchers?

A. They were tracked by researchers since age 10.

B. They all left school because of school reforms.

C. They came from several different countries.

D. They are now white-collar professionals.

3.How does the author show the results of the research?

A. By listing numbers.

B. By providing examples.

C. By following the order of time.

D. By following the order of importance.

4.What is the main conclusion to the research?

A. Homes without books are vulnerable（脆弱）to financial problems.

B. Families that can afford books raise successful children.

C. Boy who love reading books earn more than girls.

D. Children who live with books earn more as adults.