以下哪个湖是中印边界湖泊？（）
A.呼伦湖
B.喀纳斯湖
C.纳木错
D.班公错
参考答案：D
一个多边形的每一个外角都等于18°，它是（ ）边形。
— Have you ever been to Shanghai?
— Yes. I there with my father last year.
A．went
B．have been
C．have gone
D．has been
