神经轴突膜上与动作电位的产生直接有关的蛋白质属于
A．G蛋白耦联受体B．化学门控通道C．电压门控通道D．机械门控通道
参考答案：C
___deer are there on the hill?
A．How much
B．How many
C．How far
D．How long
— It isn't a football, is it?
— ________ It is a basketball.[ ]
A. Yes, it is.
B. No, it isn't.
C. Yes, it isn't.
D. No, it is.
