Cách sử dụng
The word 'whistle' is a sound that is made by blowing air through your mouth. It is often used to get someone's attention or to signal something. You can use a whistle to call someone over, to start a race, or to alert people of danger. In sports, referees use a whistle to indicate the start or end of a game or to signal a foul. You can also use the word 'whistle' as a verb, such as when you whistle a tune or when the wind whistles through the trees.