crescent shape的用法和样例：
例句
- When the moon was crescent shaped people began to disappear.
月亮开始呈月牙形的时候人们就开始失踪。 - With the knowledge of Hindu trigonometric functions, two reconstructive methods, crescent and zone figure, were given by Bhaskara to prove the area formula of the sphere.
摘要婆什伽罗利用他所熟知的印度三角函数知识，给出了球表面积公式的两种证明方法，即月牙形方法和环带形方法。
