阿摩線上測驗
72. Before comet Shoemaker-Levy-9 hit Jupiter, scientists
(A) had been unaware of its existence.
(B) had been tracking it for a few months.
(C) had observed its breakup into twenty-odd fragments.
(D) had known it would not collide with the planet.
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統計： A(21), B(117), C(66), D(9), E(0) #1835534
統計： A(21), B(117), C(66), D(9), E(0) #1835534
