Immediate action must be________before it is too late.
My mother _____ all the cleaning for my family, but recently she has been too busy teaching to do it.
Mr. Smiths was busy writing a story, only ______ once in a while to smoke a cigarette.
Tom, you play the violin so well. But I ______ you can play the violin.
For more information, please send an e-mail, ____ you can also include your advice to us.
We have just heard a warning on the radio _____________ a typhoon may be on its way.