阿摩線上測驗
18. Joseph is said to _______ medicine in the past but later switched careers to become a researcher.
(A) study
(B) studied
(C) had studied
(D) have studied。
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統計： A(52), B(20), C(54), D(215), E(0) #3418384
統計： A(52), B(20), C(54), D(215), E(0) #3418384
