The students put down their pens when the teacher_____ them to stop writing.
—If you like I can do some shopping for you. —That’s a very kind __________.
—How often do you eat out? ________, but usually once a week.
There are certain _______when you have to interrupt people who are in the middle of doing something.
It’s bad ____ for a man to smoke in the public places where smoking is not allowed.
Yao Ming as well as his teammates ______ hard to win honor for China these years.