湍球塔、脱硫塔A、B是并联的。
参考答案：错
在△ABC中，若A=120°，AB=5，BC=7，则AC=______．
CPU doesn’t mean (68) . On a large computer system, a (69) links external devices to a channel.
A．the Central Processing Unit
B．Control Unit and Arithmetic/logic Unit
C．a peripheral device
D．the heart of the computer system
