現在完成時：主語+have(has)+過去分詞(done)

1.The present perfect tense is used to denote actions or states that have taken place or completed before, but the results are related to the present. That is to say, actions or states occurred in the past, but their effects still exist.

eg:I have lost my money.

He has written his name on the book.

2. The present perfect tense can be used to denote the situation that occurred at a certain time in the past and continues to the present. It is often used in conjunction with for, since.

eg:My mother has been ill for many days.

They have lived here since 2003.

3. The present perfect tense is often used in conjunction with the adverbial of past time, such as already, yet, just, before, recently, still, late, etc.

eg:He has already obtained a scholarship.

I haven"t seen much of her recently .

就兩點:1)動作發生在過去，其結果對現在有影響。如:Is Henry around? No，he"s gone to Beijing。

2)動作發生在過去，一直延續到現在。如: Henry has studied in that university for two years. Wendy has been there since 2017.