---You could have walked here.---Yes. A taxi ___________ necessary.

While a huge amount of money ___been spent stopping pollution , large quantities of water_    _still heavily polluted．

--- I’m sorry I _____ my homework at home.--- Don’t forget ________ it to school tomorrow, please.

The number of the students in our school ____ rising since 2006.

--Is there a hospital near here?--Yes,________.