It is reported in Washington Post that an unknown terrorist group has ______ responsibility for this morning’s bomb attack.
—Tom graduated from college at a very young age.—Oh, he ______ have been a very smart boy then.
It was reported that 115 miners _____ in the flooded mine for eight days were pulled out alive at last.
Police were sent out to keep the traffic ________ smoothly during the snowstorm.
Michael ________ football regularly for many years when he was young.
He liked to go to dances and parties, _____ he could have a good time just sitting and watching.