Choose the correct answer to each of the following questions or choose the best rewritten sentences.

Câu hỏi

he hard last year, he would have lost the first prize.

A. Had / studied

B. Had/not studied

C. Didn't/ study

D. If/ had studied

Đáp án
B. Had/not studied

Câu hỏi thuộc Bài tập:

______ he ______ hard last year, he would have lost the first prize.