1) I've never been to Sapa before.
2) I haven't seen him since 2010.
3) She has been watching that film since 3 o'clock.
4) The weather in Sydney isn't as hot as in Rio.
5) They have lived in New York since 2004.
6) We have written each other for 3 years.
7) Big Ben is the most famous tower in England.
8) New York is a lot younger than London.