交换设备所配备的时钟必须按有关部门批准的()实施同步连接。
A.同步网规划
B.网络规划
C.本地网规划
D.专用网规划
参考答案:A
Many people who were once _____ now get better jobs after further education. [ ]
A. out of trouble
B. in need
C. out of work
D. in question
夜间观测若无法辨明云状时()
A.则估计天空被遮蔽看不到星光的部分为总云量
B.低云量栏记–
C.云状栏记–
D.A.B.C都对