—You ran into Mr. Li ! How did that happen?—Well, _____ of us was looking where we were going. We came around the corner at the same time.
Today, when scientists examine mummies, they wear special clothing for protection _____ they breathe in harmful gas.
Wow! That’s Uncle Sam. Now he’s in Paris, _____ he?
When _____ what is most important in life, some choose money, ____ others choose friendship.
—Why haven’t you asked her to come here? — She _____ an important experiment when I found her and she _____ it.
It was when we were returning home _____ I realized what a good feeling it was to have helped someone in trouble.