this is my sister.she name is helen.哪个错了?3Q

（this）is my sister This is my sister.改为复数形式、 This is my sister(变为复数句) This is my sister.(改为一般疑问句) oh,jane,this,is,my,sister,kate. 是this is my sister kate吗 this is not my sister 缩写 This is for my sister是什么意思 This girl is my sister 对划线部分提问：（my sister)对（my sister)提问 This is my sister a什么that is my brother? And this is my sister和This is my sister的区别, This is my sister.________name is Mary.空处填什么? 什么时候用she is my sister ?什么时候用this is my sister?急!急! 什么时候用this is my sister,什么时候用she is my sister? this my sister.对my sister提问 This is my ( )dictionary.A.sister MaryThis is my ( )dictionary.A.sister Mary B.sister's C.sister Mary's D.sister's Mary's This is my sister 改为复数句快 this sister Mary is my连词成句