元素周期律是指元素性质随着（）的递增呈周期性变化。
A、电子层数
B、核电荷数
C、原子核最外层电子数
D、质子数和中子数
参考答案：B
He had to drive faster to ______ for the lost time, which is considered dangerous to the passengers.[ ]
A. take up
B. put up
C. make up
D. turn up
