. There were no tickets _____ for Friday's performance.
—Do you know ______ Tom was punished by his father?—That was ______ he refused to go to school.
This cake is very sweet. You ______ a lot of sugar in it.
To keep slim, many young girls prefer going on a ______.
—What do you think of the story? —Wonderful! It ______ my childhood.
______ life began on earth is one of the biggest puzzles that scientist found hard ______.