固体颗粒能够被自己轻得多的流体流化起来，其内在原因是流体在颗粒固体之间流动时与小颗粒产生磨擦力。
参考答案：对
电除尘在运行中应监视哪些表计和信号？
If any accident ______ here tomorrow, it will be very serious.
A．happens
B．will be happened
C．will happen
D．is happened
