A、People always know about it. B、It has been there all the time. C、People talk about it now more than in the past. D、People talk

(18) We often hear people talking about a generation gap. The name is new, but the idea is old. Young people and their parents don’t understand each other. (17) The world keeps changing. It has always kept changing. (18) There has always been a gap between generations, but more people talk about it now. Old Mr. Ellis thinks he understands what has happened: "When I was a boy, I thought the world was a beautiful place. My life was very pleasant. But when I was older, I learned about people who were treated badly, people who didn’t have enough to eat. (19) I wanted to help them, and I married a girl who wanted to help them, too. We went to meetings and talked a lot, but it didn’t seem to make much difference."
   "Our children grew up in a world of war. They didn’t know when the fighting would stop. They wanted to think about the future. But nothing could be done about it."
   "Now I have grandchildren, and they have their own ideas. They are trying to make the world better. They are trying to help other people. They’re making people listen to them. (20) I am proud of their generation."
Questions 17 to 20 are based on the passage you have just heard.
17. What causes the generation gap according to the speaker?
18. Which of the following is not true about the generation gap?
19. What does Ellis see about himself and his wife?
20. What does Ellis see about his younger generations?