1 these are your sister 改成复数怎么改 2 they are my familys

1 these are your sister 改成复数怎么改 2 they are my familys 为什么this is a XXX改复数,有时改成these are 有时又改成they are? (1)This is Gina's sister.改成复数句 (2)Are those your friends?(作肯 填入合适的代词 1Are these your books?Yes,they are .2 Tom's sister i This is my friend 和 These are my sist 改成否定句怎么改啊,急... Are these your pen----- No,they are my brothers. They are my ___ photos.A.family's B.families C.familys' are they your gongd friends 改为单数或复数形式.怎么改? These are my sister给my提问 these are (they)books.those are (your) Are your sister a student?改错怎么改? Are she your sister?哪里错了,该怎么改