Some members of the staff couldn't handle Murray's condition,hard_英语解答

Some members of the staff couldn't handle Murray's condition,hard ___ they tried.
A as
B although
C when
D even if
答案选A我知道为什么,但是BCD如何使用,为什么不选BCD?

人气：167 ℃　时间：2020-05-24 12:35:14

解答

此处as引导让步状语从句,为习惯用法.如果要使用B或者D,从句结构需要调整为：although they tried hard和even if they tried hard