第29题: [填空题]The writer believes that learning a foreign language can help a person understand their own language better. 参考答案:Y 答案解析:The writer believes that learning a foreign language can help a person understand their own language
第30题: [单项选择]罹患率可以表示为 A. (观察期内的病例数÷同期平均人口数)×100% B. (观察期内的新病例数÷同期暴露人口数)×100% C. (一年内的新病例数÷同年暴露人口数)×100% D. (观察期内的新病例数÷同期平均人口数)×100% E. (观察期内的新旧病例数÷同期暴露人口数)×100% 参考答案:B