【单选题】________ the traffic jam, he wasn't late for class. [ ]
【单选题】按《国际危规》的规定,干的棉花属于 ,未经抗氧化处理的鱼粉属于 。
【单选题】She did it ______ our efforts to stop her.
【单选题】We will try again ____________ the failure.
【单选题】某单管阻容耦合共射放大电路的中频电压放大倍数为:-100,当信号频率等于上限频率 f H 时,此电路的电压放大倍数约为【 】。