—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
You shouldn’t take ______ for granted that your parents care much about you and do so much for you.
They were walking along the shore ______ a huge wave appeared out of nowhere, sweepingthem out to sea.
Wind power is an ancient source of energy ______we may return in the near future.(2010 ,上海)
If you have a job, ______ yourself to it and finally you'll succeed.(2010 .四川)
-Artistic people can be very difficult sometimes.-Well, you married one. _____.(2011.全国I)