EPON系统是一个点对多点的系统它采用MPCP协议保证ONU相互之间数据传输不冲突并通过()识别不同的ONU。
A.LLID
B.测距
C.光功率
D.MAC
参考答案:A
We have been told that under no circumstances we can use the telephone in the office for personal affairs.
A.did we use
B.may we use
C.we may use
D.we could use
二巯丁二钠对下列哪种重金属中毒治疗效果较二巯丙醇好
A.汞中毒
B.砷中毒
C.锑中毒
D.铅中毒
E.镍中毒