炉衬的破损原因主要有高温热流的作用、()、机械冲撞的作用、化学侵蚀等几方面作用。
参考答案:急冷急热的作用
It’s years since we last saw each other .So much____ that I can hardly recognize him.
A.has he changed
B.he has changed
C.he does change
D.he changes
合法性的获得首先依赖于一定的基础,这种基础就是()。