5. In our class, when the bell rang and the taacher closed his book, it was a or everyone to stand up.
| A．signal | B．chance | C．mark | D．measure |
So far, several ships have been reported missing ________ the coast of Bermuda.
| A．off | B．along | C．on | D．around |
I don't remember___________ to the airport that year.
| A．to be taken | B．being taken | C．having | D．to take |
A man does not know the difficulty of anything_________ he does it personally.
| A．although | B．if | C．because | D．unless |
There is a _________ of 1000 dollars for the return
| A．reward | B．prize | C．thank | D．praise |
Isn't it very kind __________ your parents to do that for us?
A. for B to C. about D. of