T568B直接法的第一线颜色为() ["绿","橙","白绿","白橙"]
便携式电子计量装置测探棒的本体为()管。 ["A、钛合金","B、铝合金","C、铜","D、不锈钢"]
再生时为什么比耗都大于1?
网卡的发送信号线() ["3,6","1,2","1,3","1,6"]
石油焦的质量可以用灰分、硫分、挥发分等指标来衡量,根据石油焦标准(SH/T0527-1992)中具体质量标准,其中一级品的() ["A、硫含量≧0.5%;挥发分≧12%;灰分≧0.3%","B、硫含量≧1.0%;挥发分≧14%;灰分≧0.5%","C、硫含量≧0.8%;挥发分≧14%;灰分≧0.5%","D、硫含量≧2%;挥发分≧18%;灰分≧0.8%"]
在锅炉汽包、凝汽器、油箱、油槽以及其它金属容器内进行焊接工作,应采取哪些防止触电的措施?