past tense 與 present prefect tense的分別

Simple Past (簡單過去式):

Subject + Verb (動詞過去式)

當一件事情在過去已經發生並完成左(不論係一秒前, 或一萬年前)

例句:
I just missed the bus! Now I'm going to be late for school.
When dinosaurs walked the earth, there were no humans.


Present Perfect Tense (現在完成式):

Subject + have/has + past participle of verb (過去分詞)

a. 一件事開始時是過去, 一直持續到現在
She has worked on the same job for 20 years.
(佢20年前開始做呢份工,做到今日仲做緊, 所以用現在完成式)

b. 一件事在過去已經完成, 但可能會再發生
We have had three tests this semester.
(由學期開始到而家已經有3 個測驗, 由於學期未結束, 可能仲有更多測驗)

c. 一件事在過去已經完成, 但無確實講明係幾時完成(或根本唔重要)
I have seen that movie.
He has read that book.

但當如果有問幾時, 個答案就會變成簡單過去式. 如:
A: I have seen that movie.
B: When?
A: I saw it yesterday.

Past tense 用法簡單, 它是表示過去的動作, 狀態, 事實, 大致和表示過去的副詞如:
yesterday , last week 等連用

而Present prefect tense
1. 它表示動作剛剛完成的動作或狀態 e.g He has left for China 他剛去了中國

2. 凡表示過去, 到現在已完成或還在繼續, 須用 Present prefect tense
e.g. I have stuided English for five year. 我英文讀了五年了.
(雖然已經讀了五年 , 現在却還在繼續讀。)

Hope these are useful for you <>??