this is my sister还是she is my sister

this is my sister还是she is my sister she is my sister. this is my sister.she----me. she is my littie sister. ( )5.-This is my sister,she is _______ than I. 什么时候用this is my sister,什么时候用she is my sister? 什么时候用she is my sister ?什么时候用this is my sister?急!急! This is my twin sister.Both she and I ( )go She is my sister.对my sister提问 This is your sister That is my She is my sister.改成否定句 She is my sister改为同义句