One ought _____ for what one hasn’t done.
Bad program on TV may have bad _____ on children.
Was it in 1996 _____ the American astronaut succeeded _____ landing on the moon?
The news _____ the football team won the game made us happy.
Only when class began _____ that he had left his book at home.
The student couldn’t ______ what the teacher was trying to explain.