题目内容
单选题（） is a protocol for file transfer.
查看答案
搜索结果不匹配？点我反馈
更多问题
单选题（） is a protocol for mail services.
单选题 （） is a protocol for accessing and transferring documents on the WWW.
填空题 A ____is a set of rules that controls the interaction of different devices in a network or internetwork.
填空题 The ____model is a theoretical model that shows how many two different systems can communication with each other.
微信支付 
支付宝支付