Be careful! The slightest spark could _____ the fireworks.
Students are required to go out in couples, especially in the evenings, with friends ______ they get into trouble.
After a long vacation, Mike came back _________.
This sweater fits me, but I can’t afford to buy __________. I have to choose _________ which is cheap enough for me.
He suggested the problem worth paying attention ______ at the meeting.
I fixed my eyes upon the newcomer, wondering whether I ________ him somewhere before.