单项选择题
A.60%B.70%C.75%D.80%
A.180B.200C.220D.240
A.1级表误差限值的60%B.2级表误差限值的60%C.1级表误差限值D.2级表误差限值
A.2h,1hB.2h,20minC.20min,2hD.1h,2h
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