光线从空气垂直射入水中，其折射角为（　　）

⑴按2∶1的比画出三角形放大后的图形．

⑵以O为圆心，画一个直径6厘米的圆．

⑶画出房子图的另一半，使它成为一个轴对称图形．

⑷将平行四边形绕A点逆时针方向旋转90°，画出旋转后的图形．

⑸画一个上底3厘米、下底5厘米，面积是16平方厘米的等腰梯形．

阅读短文，选择正确的答案。

    Chen Jie and Chen Lin are sisters. Chen Jie is 14. She's 2 years younger than Chen Lin. But she's taller than Chen Lin. Chen Jie is 46 kilograms. She's l kilogram heavier than Chen Lin. Chen Jie likes sports. She plays sports every day. So she's stronger than Chen Lin. Chen Jie has short hair, but Chen Lin has long hair. They often wear the same size shoes. They wear size 36. They love each other.