简述产生进气涡流的方法？
参考答案：
异气屏、切向气道，旋转气道。
牛乳脱气的工艺安排一般有三步，分别是哪三步？
By definition, a spar deck is the（）.
A.lower most continuous deck not broken by water tight bulkheads
B.after most weather deck above the main strength deck
C.upper or weather deck above the main strength deck
D.deck of light construction below the main or strength deck
