—Is that Dec.21,2012 is the end of the world true?—Definitely not，but ________ must be paid to global climate change.

By this time of next Friday, I _____ to New York by the Korean Airline.

-----Tom. You look very bored and tired.-----Yes, I ______ my father on the farm until seven o’clock this morning.

They______ with each other for two years before they got married.

It was the first time that I _______ visitors since I’d moved to London.