双闭环比值控制系统实质上是由（）所组成的。
A．温度控制系统
B．中级控制系统
C．定值控制系统
D．随动控制系统
参考答案：C, D
Theme park owners _____ their profit ____ charging admission fees, ______ new brand athletic
equipment and selling souvenirs.[ ]
A. have; from; advertising for
B. make; by; advertising
C. gain; with; advertising
D. benefit; through; advertising for
