in 加时间段,句子一般用将来时态.after加时间段时,句子往往用一般过去时,after加时间点时,句子往往用将来时时.例如：
I will come here in five days.
He came here after five days.
He will come here after five o'clock.
举例说明in 和after表示时间的区别
in 加时间段,句子一般用将来时态.after加时间段时,句子往往用一般过去时,after加时间点时,句子往往用将来时时.例如：
I will come here in five days.
He came here after five days.
He will come here after five o'clock.