题目

在横线上填上合适的单位。大象重约是2 字典厚40小明大约每天睡9一条高速铁路长1318 答案：【1】吨【2】毫米【3】小时或时【4】千米或公里I've been looking for the lost key at least for half an hour, but it ________ yet. [　　] A．hasn't foundB．hasn't been found C．hasn't lookedD．hasn't been looked for