1,i saw her before (before : simple past noi 1 viec da xay ra)
2,i saw her last year (last year : noi 1 viec da xay ra nam truoc)
3,tom has never been in hanoi (has never been : chua tung toi nen phai them has)
4,i readed the novel writen by jack london serveral times before ( serveral times before : da tung doc : qua khu nen read phai chuyen thi qua khu)
5,what did u do yesterday(yesterday : qua khu hom qua)
6,you watched tv last night(last nigh : qua khu toi hom qua)
7,she was born in 1980(qua khu)
8,he hasnt written a book since last year ( since last year : 1 viec chua xay ra ke tu nam trc)
9,me green teached english in this school since he graduated from the university in 1986 ( since : noi ve qua khu )
10,how long have you been learing english ( how long )