Several weeks had gone by_____the judge realized his abuse of power,这句话为什么不可以...Several weeks had gone by_____the judge realized his abuse of power,这句话为什么不可以填when只可以用before

Question

Several weeks had gone by_____the judge realized his abuse of power,这句话为什么不可以...
Several weeks had gone by_____the judge realized his abuse of power,这句话为什么不可以填when只可以用before

Answer 1

牵扯到时态问题,before“在……之前”,前面的动作在before后面动作发生之前已经发生并完成了,也就是before前要用过去完成时.而When“当……时候”,由句意可知,空格前面用的是had done,过去完成时.所以要用before.如果用when则前面只要用过去时就可以了,不用过去完成时.