says. “And the more children there are, the less question-asking there is. ”

The study also provides an explanation for why middle children often seem to have a harder time in life than their siblings. Lewis found that in families with three or four children, dinner conversation is likely to center on the oldest child, who has the most to talk about, and the youngest, who needs the most attention. “Middle children are invisible,” says Lewis. “When you see someone get up from the table and walk around during dinner, chances are that it s the middle child. ” There is, however, one thing that stops all conversation and prevents anyone from having attention: “When the TV is on,” Lewis says, “dinner is a non-event. ”

21. The writer s purpose in writing the text is to 。

A. show the relationship between parents and children

B. teach parents ways to keep order at the dinner table

C. report on the findings of a study

D. give information about family problems

22. Parents with large families ask fewer questions at dinner because 。

A. they are busy serving food to their children

B. they are busy keeping order at the dinner table

C. they have to pay more attention to younger children

D. they are tired out having prepared food for the whole family

23. By saying “Middle children are invisible” in paragraph 3, Lewis means that middle children 。

A. have to help their parents to serve dinner

B. get the least attention from the family

C. are often kept away from the dinner table

D. find it hard to keep up with other children

24. Lewis research provides an answer to the question 。