it is difficult for us to learn a lesson in life we have actually had that lesson应填when,after,since,until?

问题描述:

it is difficult for us to learn a lesson in life we have actually had that lesson
应填when,after,since,until?

应该是until.这句话的大概意思就是说我们很难领悟一个道理直到我们真正经历时才能懂得.