英文Past Tense同Present Perfect Tense有何分別?

看到這字就用Past Tense:ago yesterday before last in the past this morning
Verb+ed
Verb不變
(變動)Verb+不規則 E.G:went/go


而看到這字就用Present Perfect Tense:just since for yet already
He,she it------has
+(變動)Verb+不規則 E.G:given/give
I we they------have



Past ：Simple past tense （簡單過去式）
Past continuous tense （過去進行式）
Past perfect tense （過去完成式）

Present：Simple present tense （簡單現在式）.
Present continuous tense（現在進行式）
Present perfect tense（現在完成式）


Future ：Simple future tense （簡單將來式）
Future continuous tense （將來進行式）
Future perfect tense（將來完成式）

Simple Past Tense ﹝一般過去時態﹞
動詞的一般過去時態的形態是：動詞的過去式
動詞的一般過去時態主要表示：過去的動作或狀態。
* 這種時態的動詞常與表示過去的副詞同用。
例如：

現在：We go now.
Do we go now?
He goes now.
Does he go now?
過去：He went yesterday.
Did he go yesterday?
*"did"是助動詞"do"的過去式，幫助說明「過去」和表示「疑問」。

現在：We often read newspapers.
過去：We read that newspaper yesterday.
*"read"的過去式亦是" read"，只是讀音不同。

現在：Can you swim?
過去：Could you swim last year?
*"could"是"can"的過去式，幫助說明「過去」及「能夠」。

現在：You may go.
過去：You might go yesterday but why did you not go?
*"might"是"may"的過去式，幫助說明「過去」及「可以」。

現在：Where are you?
過去：Where were you yesterday?
*"were"是"are"的過去式。
I was / you were / he was / we were / you were / they were

現在：There are ten students in the classroom.
過去：There were ten students in the classroom.

現在：Why do you not go to school?
過去：Why did you not go to school yesterday?
*"go to school"表示為了上課而去學校，不用"the"；
"go to the school"表示為了其他目的而去學校，要用"the"。

Present Perfect Tense
§ Present Perfect Tense
動詞的現在完成時態的形態是：
have / has + 動詞的過去分詞
動詞的現在完成時態表示：
(1) 已經完成但與現在仍有關聯的動作或狀態；
(2) 過去已經開始並持續到現在的動作或狀態；
(3) 經驗過的動作或狀態。
例如：
I have written a letter now.
﹝我現在已寫完一封信。﹞
I have written a letter this morning.
﹝我今早己寫完一封信。﹞
* 如果說話時仍屬早上，句子是對的。
I have written a letter this week.
﹝我今個星期己寫完一封信。﹞
* 如果說話時仍屬這個星期，句子是對的。
I have written a letter this month.
﹝我今個月己寫完一封信。﹞
* 如果說話時仍屬這個月，句子是對的。
I have written a letter yesterday. ﹝錯誤﹞
* 說話時不屬於昨天，句子是錯的。
應說：I wrote a letter yesterday.﹝我昨天寫了一封信。﹞
Has he gone?﹝他已走了嗎〈剛走了嗎〉？﹞
Yes, he has gone.﹝他已走了〈剛走了〉。﹞
No, he has not gone.﹝他仍未走。﹞

以下句子犯了邏輯上的錯誤：
When has he gone?﹝他何時候剛走了？﹞ ﹝錯誤﹞
* 錯誤有：1. 文法上的錯誤Grammatical mistake
2. 邏輯上的錯誤Logical mistake
既然說「剛走」，又怎能問「何時走」呢！
應說：When did he go?﹝他何時走了。﹞
He went yesterday.﹝他昨天走了。﹞

動詞的現在完成時態不能與 "when" 這個疑問副詞同用，
與其他疑問副詞同用則可，如：
Where has he gone?﹝他剛到哪裏去？﹞
Why has he gone?﹝他為何剛走了？﹞
How has he gone?﹝他剛才怎樣走的？﹞

當我跟你說：
I have gone.﹝我已走了。﹞﹝錯誤﹞
You have gone.﹝你己走了。﹞﹝錯誤﹞
He has gone.﹝他已走了。﹞﹝正確﹞
* 頭兩句犯了邏輯上的錯誤。
I have come.﹝我已來了。﹞﹝正確﹞
You have come.﹝你已來了。﹞﹝正確﹞
He has come.﹝他已來了。﹞﹝正確﹞
Where have you been?﹝你去過哪裏？﹞
I have been to City Hall.﹝我去過大會堂。﹞
I have been to school.﹝我上學回來。﹞
I have been to the school.﹝我到過學校。﹞
*"to school"為上課而到學校；"to the school"為其他目的而到學校。
I have been to market.﹝我買菜回來。﹞
I have been to the market.﹝我到過菜市場。﹞
I have been to hospital.﹝我看病回來。﹞
I have been to the hospital.﹝我到過醫院〈多指探病〉。﹞
有人看見你面色不好，問你：
Have you been sick?
﹝你曾病過嗎？﹞
Yes, I have been sick.
﹝我曾病過〈現在不病了〉。﹞
Yes, I have been sick for ten days.
﹝我病了十日〈現在仍病〉。﹞
醫生問你：
How long have you been sick?﹝你病了多久？﹞
I have been sick for a month.
﹝我病了一個月〈現在仍病〉。﹞
Have you been in America?﹝你到過美國嗎？﹞
Yes, I have been in America twice.﹝我到過美國兩次。﹞
Have you been at Shatin?﹝你到過沙田嗎？﹞
Yes, I have been at Shatin.﹝我到過沙田。﹞
Have you seen that movie?﹝你看過那齣電影嗎？﹞
Yes, I have seen that movie.﹝我看過那齣電影。﹞

Past Tense 係講你之前做過d咩...發生d咩...過去左既野
Present Perfect Tense 係強調「已經」做左. 完成左. 或未曾完成等等

大部分既Past Tense 係有「Last」month~ Yesterday, 3 years 「ago」等既字眼
Present Perfect Tense 通常都有yet already, since, for 等...或者無任何既字眼...