he is swimming across the river.变否定句、一般疑问句、肯定回答、否定回答急需

问题描述:

he is swimming across the river.变否定句、一般疑问句、肯定回答、否定回答急需

否定句:He isn't swimming across the river.一般疑问句:Is he swimming across the river?-Yes,he is.-No he isn't.