对于基带CSMA/CD而言,为了确保发送站点在传输时能检测到可能存在的冲突,数据帧的传输时延至少要等于信号传播时延的()
A.1倍
B.2倍
C.4倍
D.2.5倍
参考答案:B
下述哪项符合硫喷妥钠的理化性质()
A.系淡黄色,结晶粉末,略带甜味
B.不可溶于水
C.水溶液呈中性
D.水溶液稳定
E.不能用乳酸钠林格液作溶媒
Each of them has to write a __________ composition every two weeks.[ ]
A. four-hundreds-words
B. four-hundred-words
C. four-hundred-word
D. four hundred words