1)1.Your sister is staying in the country, isn't she? /since july/.---Yes she is. She has been stayng in the country since july.
2.He's sleeping, isn't he?/long/.---Yes ,He is. He has been sleeping long.
3.Henry's travelling isn't he?/Since october/.---Yes he is. He has been travelling since october.
4.You are working, aren't you?/long/.---Yes we are. We've been working long.
5.Your son is playing the piano, isn't he?/for two hours/.---Yes, he is. He has been playng the piano for two hours.
6.Your friend is watching TV, Isn't he?/For an hour//.---Yes he is. He has been watching TV for an hour.
7.She's reading a book , isn't she/since morning/.---Yes she is. She has been reading a book since morning.