问题描述：
一般过去时和现在完成时既然有区别,怎么两者之间又能同义句转换呢
she came here at 8 o'clock同义句转换she has been here since 8 o'clock
she came here at 8 o'clock同义句转换she has been here since 8 o'clock
问题解答：
我来补答展开全文阅读