网银证书管理中，（）证书后有效期不变，（）证书后可延长有效期。
参考答案：补发；换发
-What about your journey to Mount Hua?
-Everything was wonderful except that the car we rented________on the way back.[ ]
A．broke up
B．broke down
C．broke out
D．broke in
挖掘包扎
