36 According to the passage, which of the following is associated with plumbing materials?
(A) Pipes and fixtures
(B) Mineral content
(C) Certified laboratories
(D) Removal of acidity
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統計: A(47), B(15), C(4), D(1), E(0) #3429340
統計: A(47), B(15), C(4), D(1), E(0) #3429340