—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
With the good care taken by doctors and nurses, many patients are beginning to _________.
--- I have got a headache.---No wonder you _________ in front of that computer too long.
Water can absorb and give off a lot of heat without big changes in temperature, thus creating a ______ environment.
--- If you like, I can do some shopping for you.--- That’s a very kind ________.
Of all the books on the desk, ______ is of any use for study.