現在完成式 (Present Perfect)

文法小教室 : 連接過去與現在：現在完成式 (Present Perfect)

「現在完成式」(Present Perfect)！為什麼說它特別呢？因為它就像一座橋樑，把「過去」發生的事情和「現在」的狀況連接起來。

它的基本長相是：have 或 has + **過去分詞 (p.p.)**。

一、什麼時候用現在完成式？ (When to Use Present Perfect?)

現在完成式主要用在以下幾種情況，強調的是過去的動作/狀態**與現在的關聯**：

1. 表示「經驗」： 說明「從過去到現在為止」曾經有過或從未有過的經驗，通常不指明發生的確切時間。常與 ever (曾經), never (從未), before (以前) 連用。
例：I have been to Japan three times. (我去過日本三次了。) (表示到目前為止的經驗)
例：Have you ever eaten stinky tofu? (你曾經吃過臭豆腐嗎？)
例：She has never seen snow. (她從來沒見過雪。)
2. 表示「已經完成」的動作 (且對現在有影響)： 說明某個動作在過去的某個時間點已經完成，但重點是強調這個動作完成後對「現在」造成的結果或影響。常與 already (已經), just (剛剛), yet (尚未/已經...了嗎？) 連用。
例：I have finished my homework. (我已經做完功課了。) (所以現在可以休息了)
例：He has just arrived. (他剛剛才到。) (所以他人現在在這裡)
例：Have you eaten lunch yet? (你吃午餐了沒？) / I haven't eaten lunch yet. (我還沒吃午餐。)
3. 表示「從過去持續到現在」的動作或狀態： 說明某個動作或狀態從過去某個時間點開始，一直持續到現在，而且可能還會繼續下去。常與 for + 一段時間, since + 過去某個時間點連用。
例：I have lived here for five years. (我住在這裡已經五年了。) (現在還住在這裡)
例：She has known him since 2020. (她從 2020 年就認識他了。) (現在還認識)

現在完成式的核心結構是 have/has + 過去分詞 (Past Participle, p.p.)。

過去分詞是動詞的第三種形態（動詞三態：原形 - 過去式 - 過去分詞）。

規則動詞： 過去分詞和過去式一樣，字尾加 -ed。(work - worked - worked / study - studied - studied)
不規則動詞： 過去分詞變化不規則，需要特別記憶。(詳細列表請參考附錄)
常見例子：be - was/were - been / go - went - gone / eat - ate - eaten / see - saw - seen / do - did - done / have - had - had

(注意：主詞是第三人稱單數 He/She/It/單數名詞時用 has；其他主詞 I/You/We/They/複數名詞時用 have)

肯定句： 主詞 + have/has + p.p. ...
例：I have seen this movie before.
例：He has finished his work.
否定句： 主詞 + have not (haven't) / has not (hasn't) + p.p. ...
例：We haven't eaten breakfast yet.
例：She hasn't called me.
Yes/No 疑問句： Have/Has + 主詞 + p.p. ...?
例：Have you done your homework?
例：Has he arrived?
簡答： Yes, 主詞 + have/has. / No, 主詞 + haven't/hasn't.
例：Yes, I have. / No, he hasn't.
Wh- 疑問句： Wh-疑問詞 + have/has + 主詞 + p.p. ...?
例：What have you done?
例：Where has she gone?

現在完成式常和以下這些詞語一起使用，更能表達清楚語意：

already (已經)：通常放 have/has 和 p.p. 之間，用於肯定句。
例：I have already finished lunch.
yet (尚未；已經...了嗎？)：通常放句尾，用於否定句和疑問句。
例：He hasn't called yet. / Have you finished yet?
just (剛剛)：通常放 have/has 和 p.p. 之間，用於肯定句。
例：We have just arrived.
ever (曾經)：通常用於疑問句，問經驗。
例：Have you ever been to London?
never (從未)：放在 have/has 和 p.p. 之間，句子結構是肯定的，但意思是否定。
例：I have never seen a ghost.
before (以前)：通常放句尾，表示過去到現在的經驗。
例：I think I have seen this movie before.
for + 一段時間 (持續多久)
例：They have lived here for ten years.
since + 過去某個時間點 (自從何時)
例：She has studied English since she was a child.
recently / lately (最近)
例：I haven't seen him recently.

解答：1. have finished 2. has never been 3. Have / seen 4. have lived

解答：1. since 2. for 3. since