阿摩線上測驗
39. We need ______ the weather accurately to maintain grid stability.
(A) tracks
(B) to track
(C) tracking
(D) tracked
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統計： A(3), B(67), C(12), D(2), E(0) #3887984
統計： A(3), B(67), C(12), D(2), E(0) #3887984
