在一氧化碳中，碳元素与氧元素的质量比是[ ]
A．1∶1
B．1∶2
C．3∶4
D．3∶8
答案：C
. ----You just think of yourself! You kept me waiting for at least three hours．
----I am sorry that you _____ think so.
A．would
B．might
C．could
D．should
板式杀菌设备的操作
