某天然绿色半透明弧面型戒面,质地致密,解理发育,折射率为1.52(点测),密度为2.56g/cm3,它应该是:() ["绿松石","染色硅硼钙石","天河石"]
汽车散发出的汽油蒸气中的HC占汽车HC排放总量的()%。 ["3","7","20","40","80"]
下列疾病中,可能由空气污染引起的是(). ["色盲","哮喘","肺炎","沙眼"]
当海岸线由地形图板复照或缩放仪转绘时,其转绘误差不得超过()mm。 ["A、0.3","B、0.4","C、0.5","D、0.6"]
如何正确操作隔离开关?
架空线路定期巡视的内容有哪些?