By the time he was 4, he ______ a lot of German words.
A. had learned
B. has learned
C. learned
D. learns
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What _____ Annie ______ by the time he was ten?
A. did, do
B. did, did
C. has, done
D. had, done
He ______ to play ______ before he was 11 years old.
A. had learned, piano
B. had learned, the piano
C. has learned, the piano
D. learns ,piano
I ______ the article when they came.
A. had written
B. have written
C. had been written
D. have been written
By six o’clock they ______ twelve hours.
A. worked
B. have worked
C. had worked
D. will work
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