Huong last wrote to her parents two months ago

1.huong last wrote to her parents two months ago
- Huong hasn't..............
2.Lan is better at math than Nga 
-Nga isn't.........
3.this is the best computer I have ever used
-I've never.............
4.how long is it since you used the car
-when did.........
-how long have ............
5.this is the highest building I have ever seen 
-I have never........
6.Linh likes the country life more than the city life
-linh prefers..........
7.how ling is it since he bought the computer.
-when did........
8.I've never talked to the headmaster before
-it's the...........
9.the last time we went to london was two years ago
-we haven't............
10.it's nearly two years since I saw nhung
-I haven't..........
11.you don't need to set off early
-It's...............
12.I had a cat once,but I don't any more
-I used...........
13.minh began to collect stamps in 2000
-minh has..............
14.it's a long time since we became close friends
-we have..............
15.THe last time she visited me was five months ago
-she hasn't .....................