1) How long have you owned this beautiful house, Mr Starr?-Not so long. I've just bought it.
2) Look at Nick's clothes! I think, he was playing football.
3) I'm so tired. I've been skiing all the afternoon.
4) I've known this rule nearly all my life.
5) I have been phoning (или have phoned) him for an hour and a half. There is no answer. What has he been doing all this time?
6) If they were in Moscow for two weeks, they had already visited the Bolshoi, I think. - не уверена
7) My friend Rose had been studing (потому что начала в прошлом году и учит до сих пор) French since last year. She can speak it a little.