U2980支持哪些协议()。
A.SIP
B.H.323
C.PRA
D.H.248
参考答案:A, C, D
You should try to write ____ even when you're busy. As you know, practice makes perfect. [ ]
A. now and then
B. more or less
C. sooner or later
D. here and there
将以下程序段写成三目运算表达式: 【11】 。 if(a>b) max=a; else max=b;