间歇操作釜式反应器既可以用于均相的液相反应，也可用于非均相液相反应，但不能用于非均相气液相鼓泡反应。

The task at hand now is to (56) the programmers who still use yesterday’s software technology to solve today’s software problems. Object-oriented programming requires a new attitude toward problem (57) . Problem (57) with computer system becomes more natural. Application can (58) be translated into (59) . Although it is commonly believed that it will be easier to train new programmers to use object-oriented techniques than to (60) programmers who have substantial experience in applying conventional programming language constructs.

A．classes

B．class

C．objects

D．object