-- _____is that used for?---_____ the floor.
—My sister finished school three years ago.—What__________these years?
The couple __________.I really don’t know why.
—The Chinese astronaut Yang Liwei is here already.—I__________he__________until tomorrow.
SARS__________ in Hong Kong in the winter of 2002.
When you come into the exhibition hall,you can see a large board with a notice on it,saying visitors__________not to touch the exhibits.