Since you are in a public place, the noise of your radio must be ______ to a level that we all feel comfortable with.
—What should we pay more attention to if we go camping in the mountains? —Nothing special. Take a special pair of glasses _______ the wind there is strong and cold.
When asked to explain ________ made his lessons so exciting, the teacher kept silent.
Whenever a natural disaster happens, we should offer ____ help we could to those victims.
—May I speak to your manager at 4:00 this afternoon? —Sorry, sir. He ________ to a meeting soon.
Though having lived abroad for years, many Chinese stillthe traditional customs.