be動詞例句：

　　The man is a science teacher.

　　這個男子是一位科學教師。

　　Mary's new dresses are colourful.

　　瑪麗的新衣服色彩鮮艷。

　　I have been there before.

　　我以前去過那里。

　　My mother is in the kitchen now.

　　我媽媽現在在廚房里。

　　這四個都是陳述句，可以變成疑問句，方法簡單，把主語和“be”或助動詞對換位置即可：

　　Is the man a science teacher?

　　Are Mary's new dresses colourful?

　　Have I been there before?

　　Is mother in the kitchen now?