你说的没错。 肯定式:be(am/is/are) doing sth. 否定式:be(am/is/are) not doing sth.
如:I'm watching TV.--- I'm not watching TV. He is doing his homework. ---He is not/isn't doing his homework. They are reading English.---They are not / aren't reading English.本回答被提问者采纳