once的用法时态once用作连词时,意为“一旦……就……”,用于连接时间状语从句,相当于as soon as.如：Once you ...
标签： since的时态用法
since的用法,since的八种用法详解接时间点：如 I have stayed in that country since 1995.要求：谓v.用...
since的用法,since的八种用法详解接时间点：如 I have stayed in that country since 1995.要求：谓v.用...