Viết lại câu sao cho nghĩa không đổi: 1) We stared cooking for the party fours hours ago; 2) How long is it since they bought the house? 3) It's years since we decorated this room; 4) I've never met such a famous person before

1 we stared cooking for the party fours hours ago
we have........................
2 how long is it since they bought the house ?
when .............................
3 it's years since we decorated this room
we haven't............................................
4 i've never met such a famous person before
it's ..................................
5 they last visited me five years ago 
they haven't..............
6 I haven't been to BRISTOL for 3 years
the last time...............................
7 i have never seen a dirtier-looking dog
it's................
8 tom is ill .he became ill three days ago
tom.........
9 when did you buy this computer
how long........................
10 we last went to london years ago
we..............
it's..................
the last time..............
11 this is the first time I have visited ha noi
I.................
12 I began learning english first year ago
i have