The Olympic Games is held ________.
| A．each four years | B．every four years | C．each four year | D．every four year |
Oh, it’s so cool in the house. You _______ have turned on the air-conditioner, haven’t you?
| A． should | B．might | C．must | D．can |
Fathers often feel __________ their duty to earn more money for their family.
| A．that | B．it | C．one | D．what |
--- ________ the class done most of the work?
--- Yes, but the rest ___________ rather difficult.
| A．Has, are | B．Has, is | C．Have, are | D．Have, is |
The problem lies __________ we are now giving him a fish, not teaching him to fish.
| A．in that | B．on that | C．in which | D．on which |
We were lucky to have survived the train accident. _____, the first and last car were smashed.
| A．On top of this | B．What was worse | C．As it was | D．So it was |