goodbye doesn't always mean the end这里的mean 为什么不加s

goodbye doesn't always mean the end这里的mean 为什么不加s intelligence doesn't mean doesn't mean angthing success in the lab doesn't always mean immediate success on it doesn't mean that you must always like the subject.it doe What does that word mean? 中的mean为什么不加s ? I didn't mean to break the grass.为什么mean后面要加to? smiled doesn't mean happiness smalie doesn`t mean,happy it don't mean a thing为什么不是doesn't what does it mean的mean要不要加S 为什么mean后面加了S是对的