NA+由细胞外液进入细胞的通道是
A．电压门控通道
B．化学门控通道
C．电压门控通道或化学门控通道
D．载体蛋白
E．缝隙连接
参考答案：C
________see the children before they went to bed, he came home early
A．So as to
B．In order to
C．So that
D．In order that
液压传动有何优缺点？
