—Did you see the traffic accident yesterday?
—Yes, I saw it________when I ________ past the school gate.
A. to happen; walked B. happen; was walking
C. had happened; was walking D. was happened; walked
—Did you see the traffic accident yesterday?
—Yes, I saw it________when I ________ past the school gate.
A. to happen; walked B. happen; was walking
C. had happened; was walking D. was happened; walked
B