1. 過去式, 即是所有發生的事已經過去, 無時間的規限, 過去就是過去... 通常會見到這些字, ago, yesterday, last week (Verb + ed) 如: I went to Mongkok yesterday. I played football yesterday. I lived in Hong Kong two years ago.
2. 現在完成式, 一些在過去開始,而到現在仍在進行中的事情。(+ has/ have + p.p.) 通常會見到這些字, since, for, etc. 如: I has played the piano for 3 hours. Johnny has worked in Hangseng bank since 1992. He has worked in the same company for over 10 years.
3. 過去完成式, 在過去某一個時間前完成,有時間的規限。 當你談及兩件過去(past)的事情,而兩件事有先後之分的話;較早發生的一件事,便用過去完成式。(+ had + p.p )如: I had finished homework by 5pm yesterday. The film had started when we arrived the cinema yesterday.