一台数字保护接口通过光纤PCM/SDH设备最多可传输个()命令。
A.4
B.6
C.8
参考答案:C
泌尿系结石按病因分为()。
A.代谢性结石
B.感染性结石
C.药物性结石
D.特发性结石
E.含钙性结石
We don’t know who ____ for the murder, but the policemen will tell us the truth soon.
A.is to blame
B.is to be blamed
C.is blaming
D.is to be blaming