影响酶促反应速度的因素不包括
A．底物浓度B．酶原的浓度C．反应环境的pHD．反应温度
参考答案：B
低压断路器的最大分断电流（）其额定电流。
A、远大于
B、略大于
C、等于
D、略小于
The doorbell had been ringing for several minutes before it ______.
A answered B had answered C was answering D was answered
