单项选择题
The Internet is a （）system of interconnected computer networks that use thestandard Internet protocol suite (TCP/IP) to serve several billion users worldwide.
A.global B.regional C.local D.national
单项选择题 接续质量是指用户通话被接续的速度和难易程度，通常用（）丝上和接续时延来衡量。
