1.they are waiting for a taxi.改否定句 2.my mother is cleaning the room now.改否定句
问题描述：
1.they are waiting for a taxi.改否定句 2.my mother is cleaning the room now.改否定句
教教我吧,不然老师会骂死我的!
答
They are not waiting for a taxi.
My mother is not cleaning the room now.
are not 和 is not 也可以简写为 aren't 和 isn't.不过不简写也可以.