彗发

例句：

1. 1. The tail of a comet is visible from Earth during the night sky.
   在夜空中，彗星尾巴是可见的。
2. 2. The tail of the comet was visible for several days before it disappeared behind the sun.
   彗星尾巴在消失前持续了几天才看不见。
3. 3. The tail of the comet was so long that it stretched across the entire width of the sky.
   彗星尾巴非常长，横跨整个天空。