阿摩線上測驗
4. Trilobites, a group of spineless animals, flourished in the oceans for several hundred million years ______ some 200 million years ago.
(A)until they became extinct
(B)and their extinction
(C)that were extinct
(D)because their extinction
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統計： A(207), B(5), C(49), D(7), E(0) #589473
統計： A(207), B(5), C(49), D(7), E(0) #589473
