单选题  Questions 17—20 are based on the following talk.You now have 20 seconds to read Questions 17~20.
单选题 What kind of chances are children in America today denied?
【正确答案】 A
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单选题 For what purpose were those five hundred critically ill patients investigated?
【正确答案】 D
【答案解析】
单选题 What does the need of a dying patient for company show?
【正确答案】 A
【答案解析】
单选题 What may be concluded from the talk?
【正确答案】 C
【答案解析】