1 When_______,the museum will be open to the public next year.

1 When_______,the museum will be open to the public next year.
A.completed B.completing C.being completed D.to be completed
2 _______in thought,he almost ran into the car in front of him.
A.Losing B.Having lost C.Lost D.To lose
3 -You look very tired.______at all last night?
-No,not really .I'm tired out now
A.Do you sleep
B.Were you sleeping
C.Did you sleep
D.Had you slept
..但是第三题的答案是B,我想知道为什么