By the time Jack returned home from England, his son from college. A. graduated
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By the time Jack returned home from England, his son from college.
A. graduated B. has graduated C. had been graduating D. had graduated
试题答案
D
考查动词的时态。句意为“当杰克从英国返回家时，他的儿子已经大学毕业了。”by the time到…时候为止，一般与完成时连用。选D。