在结构化布线系统中，传输介质通常选用双绞线和　【 】　。

应提供污染物如重金属，外来有机物和无机物的限度试验的结果。

A．Limit test for heavy metals and foreign organic and mineral matters should be given．
B．Limit test for contaminants should be provided, such as heavy metals, foreign organic matters and mineral matters．
C．Limit test for arsenic and lead should be given．
D．Limit test for pesticides may be needed．
E．Limit test for stemand rachis fragments in the leaves and leaflets,should be given．
找出相应的英文