阅读理解。 Most people in Britain live in small family groups. More than a quarter of homes in Britain have only got one person in them. Some of these are old people but some are people of twenty or thirty who choose to live alone. 35% of homes have two people in them, and another 17% have three people. 15% have four people in them, and the other homes have five or more. The families in Britain are small. It is unusual for parents to have more than two children. When children are about eighteen or nineteen, they leave their parents' homes, and they often go to different cities. Sometimes they only visit their parents two or three times a year. 1. How many homes in Britain have 3 people living in them? [     ] A. 8% of homes. B. 15% of homes. C. 17% of homes D. 35% of homes. 2. At what age do children in Britain usually leave their parents' homes? [     ] A. About 18 or 19. B. About 20 or 21. C. About 25 or 26. D. About 30 or 31. 3. What is the passage? [     ] A. An invention. B. A report. C. A. play D. A joke. 4. What does the passage mainly tell us? [     ] A. Young people in Britain. B. Old people in Britain. C. Families in Britain. D. The population in Britain. 5. According to the passage, which of following is right? [     ] A. There are 25% of homes have 3 people in them. B. There are 25% of homes have 2 people in them. C. There are 25% of homes have 1 people in them. D. There are 35% of homes have 3 people in them.