操纵
In order to prepare a lecture, one must do a lot of research and spend plenty of time _____ his material so that his speech is clear and easy to follow.
In order to prepare a lecture, one must do a lot of research and spend plenty of time \_\_\_\__ his material so that his speech is clear and easy to follow.
某加热炉温度控制系统如图所示,则该系统的操纵变量是( ),被控变量是( )
某加热炉温度控制系统如图所示,则该系统的操纵变量是( ),被控变量是( )C