神经细胞绝对不应期中，钠通道处于
A．失活状态
B．备用状态
C．激活状态
D．复活状态
E．适应状态
参考答案：A
When their parents were out on vacation, the house was left ________ Dick. [ ]
A. in charge of
B. in the charge of
C. taking charge of
D. taking the charge of
磷化是车身金属基材重要的表面预处理工序，磷化膜的厚度一般控制在（）。
A、<3μm
B、>3μm
C、3～8μm
D、<10μm
