Question

did you see bob at the party? No .by the time i got there,he( ). Awould leave B was leaving C

left D left

Answer 1

had left.
你在派对上看到BOB了吗?
没有.等我到那里的时候,他已经走了.

Answer 2

had left
by the time后面的从句用一般过去时，主句用过去完成时 好像是这样