2014年英语六级语法复习：一般现在时代替完成时

　　1) 有些动词用一般现在时代替完成时：

　　hear, tell, learn, write , understand, forget, know, find , say,　remember.

　　I hear he will go to London.

　　I forget how old he is.

　　2) 句型 It issince代替It has beensince

　　3) It is five years since we last met.