题目

等比数列的各项均为正数，且，则（   ） A．2017         B．2018       C．2019       D．2020 答案：B  — Why haven’t you asked her to come here?— She _______ an important experiment when I found her and she _______ it.A．had done; didn’t finishB．was doing; hasn’t finished C．did; wouldn’t finishD．did; hadn’t finished