水封逆止阀的作用?
参考答案:
煤气放散时,水封逆止阀的气缸将圆阀体推上,切断通向煤气柜的管路,防止煤气倒流或放散气体侵入煤气柜。煤气回收时,将阀体推下,切断放散管路。
原发性高血压患者的血管病变是()
A.肾动脉病变
B.脑动脉病变
C.冠状动脉粥样硬化
D.细小动脉硬化
E.主动脉的粥样硬化
It's_________ to work out this problem. You needn't go to the teacher.[ ]
A. enough easy
B. easily enough
C. easy enough
D. very easily