单项选择题
A.70% B.80% C.90% D.95%
A.0.1~0.2m B.0.2~0.3m C.0.2~0.4m D.0.3~0.5m
A.衬砌厚度测量 B.洞门里程测量 C.变形观测点测设 D.永久水准点测设
A.12m B.10m C.8m D.6m
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