从内在属性上看，职业道德具有什么？
参考答案：
职业内容上的稳定性
He is not ________ to do his homework. So he always makes some mistakes. [ ]
A. careful enough
B. enough carefully
C. carefully enough
D. enough careful
气瓶从充装介质上分类有（）、（）和（）。
