He had a lot of friends, only a few of ______ invited to his wedding.
Do ____ you think is right, ____ difficulties you may have.
—Why can't I smoke here? —At no time__________ in the meeting-room
______ it is true that a student’s most important goal is to do well in his or her studies, it doesn’t need to be the only goal.
He devoted most of his time to his research, believing his hard work would___sooner or later.
China, a country with 145 million elderly people, will remain _______ ageing society during this century, according to _______ Chinese population experts.