葡萄糖顺浓度梯度跨膜转运依赖于细胞膜上的（）。
A.脂质双分子
B.紧密连接
C.通道蛋白
D.载体蛋白
E.钠泵
参考答案：D
—Bruce was killed in a traffic accident.
—__________ I talked with him yesterday morning.
A．What a pity!
B．I beg your pardon?
C．Sorry to hear that.
D．Is that so?
常用液压泵是怎样分类的？
