Nobody in our class is able to solve the difficult problem.
A.work on B.work for C.work out D.work about
An interesting thing happened yesterday morning.
A.took the place of B.was held C.taken place D.took place
One way for you to lose weight is to eat less before you go to bed.
A.lose way B.less heavy C.is not fat D.be thinner
Parents should be________（负责）for their children's studies.
I can't________（买得起）to buy the car, because I don't have enough money.
We are doing a________（调查）about the health problem.
