As a doctor , it’s against my ______ to accept gifts from patients. 

Every weekend my younger brother will go to help the old man far away my house,for which he often received some            from the old man,such as a pencil and some sugar.

When delivering a speech, you should adjust your language to the age of your ______ audience.

After long and hard work, the police at last discovered the         of the baby found by the side of a road.

― Did you go to the 2010 Shanghai World Expo?― Yes, my father took me there. It was really __________!