Question 21 is based on the passage you have just heard

听力原文

    (19) Some people say if kids didn’t have to go to school, they’d all be out in the streets. My reply is: No, they wouldn’t. First, even schools stayed just the way they are, children would spend at least some time there because that’s where they’d be likely to find friends. Second, schools wouldn’t stay the way they are. They’d get better, because we would have to start making them what they all to be right now. (20) Last, if we stirred up our brains and gave children a little help, those who did not want to go to school could find other things to do—things many children now do during their holidays.

    (21) There is something easier we could do. We need to get the kids out of school buildings, give them a chance to learn about the world at first hand. In Philadelphia and Portland, Oregon, plans are being drawn up for public schools that won’t have any school buildings at all. That will take the students out into the city and help them to use it and its people as resource. In other words, students, perhaps in groups, perhaps independently, will go to libraries, museums, exhibitions, courtrooms, radio and TV stations, meetings, businesses and laboratories to learn about their world and society at first hand. A small private school in Washington is already doing this. It make sense. We need more of it.

21. What does the speaker say is the easier thing we could do?

解析：D。本题目为细节题。问题为：讲话者说什么是我们能做的最简单的事情？根据原文可知，讲话者说到我们可以做一些更容易的事情。我们需要让孩子们离开学校，给他们一个直接了解世界的机会。故正确答案为D。