阿摩線上測驗
128. The factory has implemented strict safety protocols to prevent accidents_______heavy machinery operation.
(A) while
(B) during
(C) when
(D) as
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統計： A(106), B(414), C(75), D(86), E(0) #3823428
統計： A(106), B(414), C(75), D(86), E(0) #3823428
