六效管式降膜蒸发器组最后一效产生的二次蒸汽进入（）。
A、热水封槽
B、预热器
C、闪蒸器
D、水冷器
参考答案：D
(江苏省南通市2009期末调研)Young people who have got jobs may realize university lessons can’t be the only preparation for all of the situations ________ appear in the working world.
A．where
B．when
C．that
D．what
A．mgtgθ
B．mgsinθ
C．μmg
D．μmg
mgtgθ
mgsinθ