they can swim 变一般疑问句和否定句
问题描述：
they can swim 变一般疑问句和否定句
答
一般疑问句：Can they swim?
否定句：They can't swim.
答
Can they swim?
They can't swim.
答
一般疑问句：Can they swim?
否定句：They can't swim.或 They can not swim.
答
Can they swim?
No, they can't.