Passage Two
"Go to the playground and have fun", parents will often say to their kids. But they should remember playgrounds can be dangerous. Each year about 200,000 children end up in hospital emergency rooms with playground injuries. Many injuries involve falls from too high equipment onto too hard surfaces. [29]Nearly 70 percent of the injuries happen on public playgrounds. Recent studies show they may be badly designed-their protective surfaces are inadequate, and their equipment is poorly maintained. Parents should make sure that the equipment in the playground is safe and their children are playing safely. Last year, the national program for playground safety gave the nation's playgrounds a grade of C for safety after visiting more than 3,000 playgrounds nationwide. [30]Parents should watch closely. They should always be within shouting and running distance of their children. Young children don't understand cause and effect, so they may run in front of moving swings. They're also better at climbing up than getting down, so they may panic at the top of a ladder. It's important for children to know you're watching them. [31]Once they feel that sense of security, that's when they can be creative.

Questions 29 to 31 are based on the passage you have just heard.
29. What is the cause of playground injuries?
正确答案：C
解析：题目询问导致孩子在操场上受伤的原因是什么。关键是要听到“差不多有70%的伤害都是在操场上发生的。近期的研究表明，这些操场的设计粗糙——保护层不足，器材的维修保养很差。”即C（操场的状况很差）。选项A、B、D的内容文中均未提及。
30. What should parents do to prevent playground injuries?
正确答案：B
解析：题目询问为了防止孩子在操场上受伤，父母应该做些什么。关键是要听到“父母应该密切注视（孩子们）”。B是原文的同义表达。A、C、D的内容均与原文不符。
31. What does the speaker say about young children?
正确答案：D
解析：题目询问作者说小孩子时怎么样的。关键是要听到最后一句：“一旦（小孩子）有了安全感，他们就能够发挥创造力。”D是原文的同义表达，故为答案。