银行卡收单业务受理终端密钥管理应遵循一机一密原则。
参考答案：对
It was about 600 years ago ______the first clock with a face and an hour hand was made. [ ]
A. that
B. until
C. before
D. when
北回归线穿过的我国省区有（）
A台湾、福建、云南
B广东、广西、海南
C江西、广西、台湾
D台湾、广东、广西
