the 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﹞


現在式 現在分詞 過去式 過去分詞
be(am,are,is) being was/were been

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。﹞

可參考以下網址: http://www.npc.edu.hk/staff/~ngtungying/english_grammar/lessons/lesson22.htm

Present prefect tense is used

1. for past actions whose time of doing the action is no9t given or is not very clear
2. with the words for, since, recently, lately: and
3. with the words ever, never, before, and yet