simple past &presant perfect ??????????

simple past基本上可以直譯成過去式~~~
即係個事件/動作已完成, 過去了~~~ 你就可以用simple past tense~
用係邊? 就最通常到 d "yesterday", "last.xx...", last summer, eg. last year, i went to China.
而點用就..... 只要將個verb (動詞) 轉做past tense 就得~ eg. go-> went

present perfect, 字面上解作現在完成式....就即係剛剛過去/完成了.....
最通常見到 "already", "just" 咁的字就會用呢個tense...
eg. i have just returned a book.
用法: 係 verb 前加上 have / has, 而verb 要轉用past paticiple, 過去分詞先 ok!
eg. have + returned

Simple past 同 Present perfect 兩個時式都係表示已發生了的動作,但他們的分別是在simple past tense 的句子中有時間詞"time expression" (例: last week, yesterday, etc), 而present perfect tense就沒有。

PAST TENSE
- talk about completed actions in the past:
eg. He did not work very hard yesterday.

* Irregular verbs: There are many irregular verbs which do not follow the regular form of the past tense. These include go (went), have (had) and know (knew).


PRESENT PERFECT TENSE
a. talk about actions or situations which started in the past and have continued up to
the present:
eg. I have lived in Europe for 15 years (and I live there now).
b. talk about actions which happened at an unknown time in the past:
eg. They have never been to China (in their lives).
c. talk about things which were completed in the past but are important in the
present. The tense is often used in this way to give news.
eg. I have just lost my wallet (so I don’t have any money).

PRESENT PERFECT with for and since, yet and already:
We can use for and since with the present perfect tenses to talk about how long an action or situation has been going on. We use for to talk about the length of time and since to talk about when the action or situation started.
eg. I haven’t seen Brian for two days.
I haven’t seen Brian since Tuesday.

We can use yet with the present perfect tenses in questions and negatives to talk about something that has not happened, but that we expect to happen very soon. Yet always comes at the end of the sentence.
eg. Has the film started yet?
It is midnight and the film hasn’t started yet.

We can use already with the present perfect tenses to talk about something that has happened sooner than we expected. Already can come at the end of the sentence, or before the past participle of the verb.
eg. Has the film started already?
It is 6 o’clock and the film has already started.

simple past ：只須要將verb轉做過去式就可以。
例如： Here was a house before.

present perfect ：一定要有HAVE或HAS再加上一個過去分詞。
例如：I have had a house before.