句型转换：1.they are doing housework.（分别改成一般疑问句和否定句）
问题描述：
句型转换：1.they are doing housework.（分别改成一般疑问句和否定句）
2.the students are cleaning the classroom.（改为一般疑问句并作否定和肯定回答）
答
1Are they doing housework?They are not doing housework.
Are the students cleaning the classroom?.Yes,they are.
No,they aren't.