题目

祖国大陆很早就与台湾有密切联系了。三国时期吴国卫温率船队到达台湾，台湾在当时称为（ ） A . 流求 B . 澎湖 C . 琉球 D . 夷洲 答案：D— What were you doing ______ I knocked at the door?— I was sleeping.A．unless B．onceC．when D．while