It is uncertain ______ the experiment is worth doing .
He wrote a lot of novels, none of _____ was translated into a foreign languages.
______ winner, who might be the luckiest, was a housewife.
—I’m sorry to ____ you to so much trouble. —That’s all right.
______ come into leaf or bloom is obviously a sign of spring.
Mrs Read went to the market and bought several ______ eggs.