12.水管埋設管徑越大,其覆土深度如何?
(A)越小
(B)越大
(C)無影響
(D)視情況而定
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統計: A(12), B(558), C(12), D(19), E(0) #1441267
統計: A(12), B(558), C(12), D(19), E(0) #1441267