单数句变复数句的问题this is his case.变复数句后本该为：these are their cases.但是

单数句变复数句的问题this is his case.变复数句后本该为：these are their cases.但是 单数句变复数句,复数句变单数句1He is his friend.2Those are boxes.3 These ar Is your case?变复数句 请问单数句变复数句,句中的人称代词跟着变吗?例如：This is my friend,在变为复数句时,是These ar 单数句变复数句,复数句变单数 单数句变复数句 的答案! 单数句变复数句,复数句变单数句.We are boys. these are pens （变复数句) this is his pencil case 复数句 单数句变复数句,复数句变单数句.It is a bus____________________ These pens are blue.(变否定句） Is that your photo?(变复数句） This is that is his pen变复数句