精馏塔热虹吸式再沸器一般宜选用（）。
A、固定管板式换热器
B、板翅式换热器
C、箱管式换热器
D、套管式换热器
参考答案：A
The boy as well as the two dogs _____ when the earthquake rocked the city.
A．were sleeping
B．is sleeping
C．was sleeping
D．are asleep
断路器油量过多在遮断故障时会发生爆炸。
