contact face的用法和样例：
例句
- Slowly pull the assembly outward to open check allowing exposure of the seat and clapper contact area for cleaning.
慢慢将止回阀往外拉，打开止回阀，使得阀座和阀瓣接触面暴露出来便于清洗。 - We have seen oil reinvasion above this contact,water reinvasion below,or no reinvasion at all.
我们能看到油的二次侵入在接触面的上部，水的二次侵入在接触面的下部或者是根本没有。
