By the time I got to school, I realized
问题:
By the time I got to school, I realized that I ______ my pen at home. [ ]
A. have forgotten
B. have left
C. had forgotten
D. had left
By the time I got to school, I realized that I ______ my pen at home. [ ]
A. have forgotten
B. have left
C. had forgotten
D. had left