現在完成式 (Present Perfect Tense)
I have done my homework.
過去的某個動作，不久前才剛剛完成 (... just...)。
I have just done my homework.
Have you ever eaten snake?
Cindy has always loved shopping.
How long have you lived here?
Since when have you been sick?
For hours, we have heard nothing but negative criticism. Why can't you say something more constructive?
帶有 since 或 for 表時間的介系詞，通常用現在完成時式。for 表示一段時間， since 表示從過去某一時間點到現在。
Rebecca has lived here for 10 years.
Rebecca has lived here since 2001.
I have been here for two hours.
I have been here since 10 o'clock.
Mr. Yang has worked in this factory _______ 1968.
(A) in (B) since (C) before (D) for
Tina is getting married to a man she has known only _______ a month.
(A) in (B) on (C) since (D) for
帶有副詞 ever, never, still, just, already, yet 等的句子，通常需要用現在完成式或過去完成式。
Have you ever failed a class?
She has never been to Korea.
Mary has just finished her homework.
Don't forget to tell him to be here on time. ～
I have already told him.
Have you done your homework? ～
No, I haven't done it yet.
The idea of this great movie comes from a novel which has _______ been read and loved by many people.
(A) just (B) still (C) ever (D) already
"been to" 與 "gone to" 用法不同
He has been to Japan.
Have you ever been to Japan?
Yes, I went to Tokyo last month.
He has gone to Japan.
Is Andy in Japan?
Yes, he's gone to Japan. He'll be back next month.
he's = he has; he'll = he will