Question

这道题选什么为什么选这个答案

20. The staff members were asked to arrive a few minutes earlier before the meeting ________ .

A) will start

B) starts

C) started

D) would start

Answer 1

只能选C。原因：
一 主句是过去式，从句只能用相应的过去时态。
二 before引导的时间状语从句，只能用一般时态（即一般现在时表示现在的将来、一般过去式表示过去的将来）表示将来。
如：I'll finish the work before mom comes back from work.
I would go to see you before I got your news.