May 12, 2008 , a terrible earthquake happened in Wenchuan . Lots of buildings __________ , and many students lost their lives .
There are usually ____ people in the supermarket every weekend.
Do you know how to ____ ice into water?
Let’s try our best to ____ paper to save the trees.
We tried to stop the flames from spreading, but we knew it was ____.
My parents go to work by bike ____ by bus.