We will celebrate 
the 90th birthday of the Chinese Communist Party _____ July 1st, 2011.
| A．on | B．at | C．in | D．during |
We must______ using plastic bags in order to protect our earth..
| A．give out | B．give up | C．give away | D．give in |
Parents often ask us _____ water in our life.
| A．save | B．savin | C．to save | D．saves |
E - mail is very popular today. People hardly post letters, _____?
| A．did they | B．do they | C．didn’t they | D．don’t they |
Our country ______the sixth population census(人口普查) already.
| A．finished | B．has finished | C．will finish | D．finishes |