安静时细胞膜内K+向膜外移动是通过( )。
A．单纯扩散
B．易化作用
C．主动转运
D．出胞作用
E．被动转运
参考答案：B
The old couple have been married for 40 years and never once _____ with each other. [ ]
A. they had quarreled
B. they have quarreled
C. have they quarreled
D. had they quarreled
选择项目经理时，（）是第一位的。
A．是否是全才
B．有无类似项目的工作经验
C．有无高尚的职业道德
D．有无良好的理论知识
