什么情况下应对换热器进行检查和维修？
参考答案：
温度大幅度异常增高；换热器压降大于设计要求；换热器法兰垫片损伤严重。
Jet Li can ________. [ ]
A. does kung fu
B. Chinese kung fu
C. do Chinese kung fu
D. do China kung fu
In order to keep fit，you will take exercise_________ and eat healthily．
A．regularly
B．generally
C．extremely
D．approximately
