jup e mấy pro tri thức ơi

30.When I entered the room,everyone___B.was dancing___.
31.He said that he___A.had done___his homework since 7o'clock.
32.How long___B.have you been___able to drive?−−Since 1990.
33.She won't get married until she___A.is___25 years old.
34.This building used to be a library,___B.didn't it___?
35.Nobody was injured in the accident,___C.were they___?
36.Let's go out for a walk,___D.shall we____?