阿摩線上測驗
15. Even professional marketers are never sure _________ some new products are runaway successes while others fail miserably.
(A) for
(B) why
(C) since
(D) that
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統計： A(13), B(316), C(4), D(50), E(0) #841503
統計： A(13), B(316), C(4), D(50), E(0) #841503
