固定管板式换热器适用于壳程介质（）的场合。
A、清洁
B、易结垢
C、温差过大
D、压力高
参考答案：A
请简述企业再造的含义及特点。
In the Natural Approach，to ______ stress，learners are not required to speak until they feel ready，but they are expected to make responses in other ways.
