【基本用法】 過發現影--- 表示過去發生，對現在造成了影響。
e.g. Their parents have known the good look excited.
過發持續--- 表示從過去開始，持續到現在的動作或狀態。
e.g. I have learned English for 10 years.
經歷 --- 表示曾經做過某事，或曾做過n次
e.g. I have seen the film Titannic twice.
【時間狀語】 already, just, yet, since, since then, for, recently / lately,
so far = till / until now = up to now, in the last / past few years,
How longever, never, before, once, times
【重難點】 延續性與非延續性動詞的'用法
什麼時候才必須用延續性動詞？ 出現how long, for+時間段, since+時間點
非延續性動詞轉化
borrow keep buy have
finish / end be over begin / start be on
open be open die be dead
join be in / be amember leave be away（from）
▲ 需瞭解記憶
get up be up fall asleep be asleep
fall ill be ill, lose be lost
become be return / come back / get back be back
close be closed catch / get a cold have a cold
arrive /come / go / move / reach /get to be in /at / be here /be there
【易錯點】 in the past few years (不是 a few)
have been to, have gone to和have been in的區別
already與yet區別
since+時間點，for+時間段（since 3 years ago; for 3 years）
since 引導的從句要用一般過去時
It is /has been + 時間段 + since + 從句（一般過去時）
He came to our school in 2000, since then he has taught English here.
