It's high time that you ________ even harder at your lessons as the exam is around the corner.
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, _______?