By the time he was twelve, Edison to make a living by himself .A. would beginB. has begun

发布时间：2020-08-16 16:30:39

By the time he was twelve, Edison      to make a living by himself .
A. would begin
B. has begun
C. had begun
D. was begun

网友回答

A. would begin
B. has begun
(答案→)C. had begun
D. was begun
解析：时态题。By the time +过去时，主句谓语用过去完成时态 选C。 句意：到爱迪生十二岁时他已开始自己谋生了。
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