单项选择题

下列有关物质用途的说法错误的是（）

A.AgI可用于人工降雨
B.AgBr常用于制感光材料
C.Na2O2常用作呼吸面具和潜水艇里的供氧剂
D.BaCO3可代替BaSO4用作“钡餐”

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单项选择题

In multipoint networks , there are tree persistence methods when a station finds a channel busy.in the 1-persistent method,after the station finds the line idle,it sends its frame immediately.this method has the （） chance of collision because two or more stations may find the line （） and send their frames immediately. In the nonpersistent method , a station that has a frame to send （） the line . If the line is idle , it sends immediately If the line is not idle , it waits a （） amount of time and then senses the line again.The nonpersistent approach （请作答此空） the chance of collision because it is unlikely that two or more stations will wait the same amount of time and retry to send simultaneously The p-persistent approach combines the advantages of the other two strategies . It reduces the chance of collision and improves efficiency.

A.increases
B.equalizes
C.reduces
D.cancels

单项选择题

关于公司资产负债表，以下表述表述正确的是（）

A.如果总负债小于所有者权益,说明公司资不抵债
B.利润表是资产负债表的重要组成部分
C.总资产越大的公司,盈利能力越强
D.负债项可以说明企业的资金来源和负债情况

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