—     shouldteenagersspendatleast30minutestakingexercis...

问题详情：

—      should teenagers spend at least 30 minutes taking exercise?

    —Five times a week，according to some reports．

    A．How much    B．How soon    C．How long    D．How often

【回答】

D

知识点：相似 相近词比较

题型：选择题