Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
I would be very rich now________working long ago.
A. if I gave up
B.if I wouldn’t give up
C.were I to give up
D.had I not given up
Đáp án là D. ->D đảo ngự câu điều kiện dạng phức ( có now ở mệnh đề chính): If + S + had + PII, S+ would + V. => Had S + PII, S+ would + V.