——The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?——____ my students have a try?
Three million _______ a large number. You can make it _______.
Over fifty countries _______ the AIIB(亚投行) so far.
—Excuse me, madam. Could you please tell me _________ the bus arrives? —Sure. At 9:00.
We stopped _________, but there was not any sound.
Nancy, sweep the classroom, _______?