8.5 cease doing/to do 
cease to do　 长时间，甚至永远停做某事。
cease doing　 短时停止做某事，以后还会接着做。

　　That department has ceased to exist forever.
　　那个部门已不复存在。
　　The girls ceased chatting for a moment when their teacher passed by.
　　姑娘们在老师走过时，停了会聊天。8.6 try doing/to do 
　try to do　　努力，企图做某事。
　try doing　 试验，试着做某事。

You must try to be more careful.
　你可要多加小心。
I tried gardening but didn't succeed.
我试着种果木花卉，但未成功。