Softswitch体系中详细话单(CDR)由()提供
A.MG
B.IAD
C.Softswitch
D.0AAAServer
参考答案:C
Einstein, the famous scientist, was born ______ March, 1897.
A.at
B.on
C.in
D.to
有下列二叉树,对此二叉树前序遍历的结果为( )。
A.XZCYAB
B.XYZABC
C.XYABCZ
D.XYAZBC