一般現在時代替完成時

1) 有些動詞用一般現在時代替完成時： hear, tell, learn, write , understand, forget, know, find , say,　remember. I hear (= have heard) he will go to London. I forget (=have forgotten) how old he is.

2) 句型 " It is … since…"代替"It has been … since …"

3) It is (= has been) five years since we last met.