don’t sleep in class,teachers say to us.同义句转换

don't sleep in class,teachers say to us.同义句转换
teachers ask us ______ ______ sleeping in class

Teachers ask us (not to) sleep in class.
老师们叫我们不要上课睡觉.
ask sb not to do,叫某人不要做.
再问： 谢谢你的回答。不过sleep是ing形式，请问怎么写呢？
再答： Teachers ask us (to stop) sleeping in class. stop doing，停止做某事。