問題詳情

39. Once mainly ________ in banks and government buildings, video surveillance systems have now become standardequipment for most stores in Taiwan.
(A)are seen
(B)to see
(C)seen
(D)having seen

參考答案

答案：C
難度：適中0.465116
統計：A(11),B(8),C(40),D(16),E(0)