A model or an experiment in a science class can help students see things which would ______ remain hidden.
According to a recent U. S. survey, children spent up to 25 hours a week __________ TV.
—Why didn't you give a hand to the boy?—I __________ but he __________ to his feet before I tried to.
We tried to find a table for seven, but they were all __________.
Our English teacher asked our monitor if all of the students __________ their homework on time.
So sudden __________ that the enemy had no time to escape.