this改为复数形式

this改为复数形式 This is my sister.改为复数形式、 This is my friend 改为复数形式 this is a book改为复数形式 Is this your friend?改为复数形式 This is a dress.改为复数形式 This is my cousin.改为复数形式. What's this?怎么改为复数形式 This is his cousin.改为复数形式 This is a cat.(改为复数形式) This is her baby.改为复数形式 This is a box.改为复数形式 This is an arm.改为复数形式 This is a pen.(改为复数形式) This is my brother.改为复数形式急 How much is this black skirt?(改为复数形式) This book is in that box.（改为复数形式） this stamp is from canada.(改为复数形式）