You must turn off your cell phone when you take a plane改为否定句形式的同义句
问题描述：
You must turn off your cell phone when you take a plane改为否定句形式的同义句
答
you must not turn on your cell phone when you take a plane
答
You can not turn on your cell phone when you take a plane.
答
You mustn't turn on your cell phone when you take a plane.
祝楼主愉快
mustn't后turn off 要换成他的反义词turn on
答
you mustn't turn on your cell phone when you take a plane.
答
You mustn't turn on your cell phone when you take a plane.