第1个回答 2022-10-29
现在完成时的标志词有以下这些：
1、Already：用在肯定句中（be动词、助动词、情态动词之后，实意动词之前）常与yet进行转换。例如：I have already finished the work.我已经完成这项工作了。 改为否定句：I haven't finished the work yet.我还没有完成这项工作。
2、just, before, recently, still, lately, never, ever, twice, on several occasion, in the past/last few days/weeks/months/years, this morning/week/month/year（多用于一般过去时）, so far, up to now, till now。
3、since+时间点=for+时间段since+一般过去时态的时间状语从句=since+时间点+agosince+一般过去时态的时间状语从句。例如：He has been here since he joined the army。自从他参军以来，他一直在这儿。