-Where’s the old blue bag?- I’m not sure, but it ______ be thrown away. It be somewhere in the house .I saw it yesterday.
Xi’an is a city with many places of interest and _____ tourists come here every year.
—_____ you _____ your homework yet? —Yes, I _____ it ten minutes ago.
It’s necessary for you _____ exercise every day.
—Could you tell me _____? —Sorry, I don’t know.
The Greens _____ China for seven years.