Your sister is a tudent肯定回答
Is your sister a student?Yes ,she is.
They are my friends否定回答
Are they my friends?No,they aren't
She`s her aunt否定回答
Is she her aunt?No,she isn't
I`m his uncle 否定回答
Are you his uncle?No,I'm not
无疑后请采纳.
书山有路勤为径,学海无涯苦作舟.
-----------与君共勉-----------