阿摩線上測驗
123. Before the clinical trial begins, scientists must ______ verify the purity of all chemical compounds.
(A) rigorous
(B) rigor
(C) rigorously
(D) rigorousness
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統計： A(29), B(25), C(164), D(1), E(0) #3823143
統計： A(29), B(25), C(164), D(1), E(0) #3823143
