---Look at the boy running on the playground. Is it David? ---It ______ be him. I saw him go to the teachers’ office just now.
How did you________the weekend?
—What did you do last weekend? —On Saturday afternoon,I________soccer.
—Li Lei’s weekend? —It was pretty good.
Hundreds of students came to Shaoxing to work________the World Choir Games in 2010.
—When does your mother go shopping? —Usually________Sunday morning.