When hearers, topics and environments change, the speakers' speaking styles vary. There are five different styles: frozen, formal, consultative, casual and intimate. Which of the following statements is an example of formal style?

A、 Visitors should go up the stairs at once.
B、 Would you mind going upstairs right away, please?
C、 Time you all went upstairs, now.
D、 Up you go, chaps!

【正确答案】 A

【答案解析】 选项A为正式体的形式；选项B为商议体的形式；选项C为随便体的形式；选项D为亲密体的形式。