阅读：奇妙的自然现象 — 英语词汇题
题目
阅读短文，并根据短文内容填空。On a clear night, moonlight can pass through tiny drops of water in the air. The drops bend the light and make a pale bow in the sky. This rare sight is called a moonbow. Unlike a rainbow, it is made by moonlight. 根据短文，月光穿过空气中的小水滴形成的弧形景象叫作 a ______。