It was when she was about to go to bed ______ the telephone rang.
He talked about the classmates and the school ___ he had visited.
Americans eat __ vegetables per person today as they did in 1910.
I wonder if you know it ___ .
The number of people invited ___ fifty, but a few of them ___ absent for different reasons.
—George is a wise person.—But in my opinion, he is ___ than wise.