四辊支承辊采用唇形密封圈,唇的方向朝外主要目的是()
A.防止油脂泄漏
B.防止氧化铁皮及水的进入
C.装配方便
D.便于散热
参考答案:B
-–What do you think of the lecture?
--____but interesting, but I’ve managed to survive it.
A.Nothing
B.Everything
C.Anything
D.Something
的值是()
A.
B.1
C.
D.