1．聽第四段材料，回答第15至17小題． 15．Who has ever been to Taiwan？ A．Mary． B．Bill． C．Mary's parents． 16．How will Mary and her parents get to Taiwan？ A．By ship． B．By train． C．By plane． 17．How much will Mary and her parents pay for their round?trip tickets？ A.3，000 yuan． B.5，400 yuan． C.6，000 yuan．
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