同车道行驶的车辆遇前车有下列哪种情形时不得超车？
A．正在停车
B．减速让行
C．正常行驶
D．正在超车
参考答案：D
声能密度
What the educational expert wants to stress is that ________ from worry and anxiety can definitely contributes to a child’s mental and physical health.
A．responsibility
B．freedom
C．sorrow
D．comfort
