单项选择题
A.400t B.600t C.800t D.1000t
A.1900,1800 B.1800,1800 C.1900,1900 D.1850,1850
A.细砂 B.中砂 C.粗砂 D.无法判断
A.5L B.10L C.20L D.30L
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