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
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
A。
由语境逻辑可知，人的一生难以吸取教训的状态一直延续到真正有了教训，因此该空应填until引导时间状语从句。