描述物品形状：It's a... — 英语选择题
题目
手工桌上有一张三角形的纸牌和一个圆形的杯垫。哪一组英文描述正确？A. The paper card: It's a circle. The coaster: It's a triangle. B. The paper card: It's a triangle. The coaster: It's a circle. C. The paper card: It's a square. The coaster: It's a rectangle. D. The paper card: It's a rectangle. The coaster: It's a square.