When Hugo got to school, he realized that he … his notebook at home. (leave)
was leaving
had left
left

I … to London with my cousin last August. (fly)
was flying
had flown
flew
We found the film interesting, because we … it before. (not see)
hadn’t seen
saw
were seeing

Alan called me last night, but I didn’t hear the phone because I … . (sleep)
was sleeping
slept
had slept


What time … the concert … last night? (finish)
did, finish
was, finishing
had, finished