The patient insisted that he _______ ill and _______ to the hospital. A) wasn't, wasn't sent B) wasn't, shouldn't be sent C) shouldn't be, wasn't sent D) shouldn't be, shouldn't be sent
【简答题】已知电路如图,如果输入电压始终等于 -1V,开关S处在闭合位置时,输出电压为( )V; 开关S断开之后1ms时刻, 输出电压为( )V; 开关S断开之后2ms时刻, 输出电压为( )V。 如果输入电压是一个随着时间变化的电压信号 , 开关在 t = 0 时刻断开, 那么在此之后,输出电压与输入电压之间关系是下面哪一个? A B C D