1 It's for ages since I  played football. 

-> sau since + thì QKĐ 

2 It's three years since I  went to Ha Long.

-> sau since + thì QKĐ

2 the last time I went to Ha Long was three years ago.

-> thời gian + ago là dấu hịu của thì QKĐ 

3 She last saw her mother when she left for Paris

-> thì QKĐ 

-> s + v2 

4 I haven't gone to Hanoi for over four years

-> thì HTHT + for 

-> ta có cấu trúc : S + have / has + VPII + for + 1 khoảng thời giann 

4 It's over four years since I last went to Hanoi.

-> sau since + thì QKĐ 

5 I haven't seen her since she returned to her home town.

-> vế I haven't seen là thì HTHT ta có cấu trúc : S + have / has + VPII 

-> vế since she returned to her home town. là sau since + thì QKĐ