現(xiàn)在完成時可以用來表示發(fā)生在過去某一時刻的,持續(xù)到現(xiàn)在的情況,常與for,since連用.

　　Mary has been ill for three days.

　　I have lived here since 1998.

　　現(xiàn)在完成時往往同表示不確定的過去時間狀語連用,如already, yet, just, before, recently,still, lately等:

　　He has already obtained a scholarship.

　　I haven't seen much of him recently (lately).

　　We have seen that film before.

　　Have they found the missing child yet