Many children are ____ in the countryside when their parents flood into the cities for jobs.
We Chinese ______ the Olympic Games in 2008.
Mott is out. But he ______ here a few minutes ago.
---Hi, Tom. ---Hello, Fancy. I ______ you were here.
He promised to tell me by himself when I ______.
--How long ______ he ______ a fever? --- Ever since last night.