真空蒸发时引起温差损失的原因是什么?
参考答案:
溶液的沸点升高;由液层静压效应引起的温度差损失。
29. Only ____ did she realize the stress he was_____.
A.then; under
B.when; on
C.when; at
D.then; with
Look at the trouble I am in! If only I _____ your advice. [ ]
A. followed
B. would follow
C. had followed
D. should follow