架空光（电）缆的金属护层及架空吊线应隔多长距离做一处保护接地（）。
A.0.5km
B.1km
C.2km
D.3km
参考答案：C
按顺序排列。
1. evening morning afternoon
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2. Sunday Monday Wednesday Thursday Saturday Tuesday Friday
In that school, English is compulsory for all students, but French and Russian are________.[ ]
A. special
B. regional
C. optional
D. original
