Duty is a course of action that people you to take by social customs , law or religion.
—Why didn't Mr.Smith arrive on time for the meeting?—He must have been ________ on his way here in the traffic jam.
With economy developing at great speed, our city has ________ quite a few changes in recent years.
Many people are beginning to reflect on why we pay so much to study abroad and what kind of consequences it will ________.
The famous actor keeps fit by ________ for an hour every morning.
WikiLeaks founder Julian Assange was in court today, and when asked for his address he said he didn't want to ________ that information.