固定床反应器具有反应速度快、催化剂不易磨损、可在高温高压下操作等特点,床层内的气体流动可看成()
A、湍流;
B、对流;
C、理想置换流动;
D、理想混合流动。
参考答案:C
指出下列各句所用的修辞方法。
1.井冈山是中国革命的摇篮。 ( )
2.春雨贵如油。 ( )
3.烽火连三月,家书抵万金。 ( )
4.春雨像牛毛,像花针,像细丝。 ( )
– Were you late for work yesterday morning?
– Yes. By the time I got to the bus stop, the early bus .
A. has already left B. is already left C. had already left