It is difficult for us to learn a lesson in life _____we’ve actually had that le

题型：不详难度：来源：

It is difficult for us to learn a lesson in life _____we’ve actually had that lesson.

A．until

B．after

C．since

D．when

答案

A

解析

until引导时间状语从句,意为“直到……”,表示主句的动作一直延续到until从句中动作发生前。after 意为“在……之后”。since 意为“自从”,常与现在完成时连用,表示动作从过去的某个时候开始,一直延续到现在的动作。when 意为“在……时候”。