软交换传输控制协议有哪些?
参考答案:
TCP,UDP,SCTP
Dina,_______ for months to find a job as a waitress,finally took a position at a local advertising agency. [ ]
A. struggling
B. struggled
C. having struggled
D. to struggle
电磁波的表达方式可作三种基本的调制方式()、()、()。