Is that her English book?复数形式

Is that her English book?复数形式 That is an English book的复数形式 That is an English book.给为复数形式 改为复数形式 Is that an English book?What"s this in English?It is it is her book复数形式 That is an English book变成复数 Whose book is that?改为复数形式 英语句子单数变复数1、Is that her English book?(改成复数)2、Those aren't Chi is that her counsin 的复数形式 Is that her cousin?复数形式 That's an English book.(改为复数形式) 按要求改变句型.1.Is that her English book?（改成复数） 2.Those aren＇t Chi