The young waiter knocked over the red wine by chance, ____ the table cloth.
Some people think clowns are only funny for children. _____________ , they can help people forget their problems, at least for a short moment.
A smile can help us _____________ difficult situations and find new friends in a world of strangers.
We should all remember that some great scientific discoveries _____________ by chance.
I had only a few _____________ with Miss Gao, though we work in the same school.
In case it thunders, we’d better _____________ the electricity at once and turn off the TV.