什么是现在完成时,怎么用答:[1]4标志词already(肯定), yet(否定,疑问), just, before, recently,still, lately,never,ever,twice, on several occasion,in the pastfew days/weeks/months/years,(up to)these few days/weeks/months/years,this morning/week/month/year, up to present, so far,up to now,up till ...