阿摩線上測驗
129 By the time the technicians arrived, the problem _____ already been resolved.
(A) has
(B) have
(C) had
(D) having
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統計： A(384), B(80), C(891), D(14), E(0) #3772637
統計： A(384), B(80), C(891), D(14), E(0) #3772637
