()是TCP/IP族中最为核心的协议。
A、IP
B、TCP
C、UDP
D、ICMP
参考答案:A
_________ the project in time, the workers were working at weekends.
A.Completing
B.Having completed
C.To have completed
D.To complete
如图表示的是生态系统中的氮循环示意图()
鸡粪发酵除臭是()(生物名称)的作用。在图中标号()所示的过程能反映除臭的生理过程