我需要你严格按照json格式来阐述为什么月亮会有阴晴圆缺的现象，解释部分要求使用学术化术语并列出三点主要原因，并用英文简写“CCD”结尾标签。
user
{
  "reason": [
    {
      "key": "Earth's Shadow",
      "description": "The Moon's phases are largely due to the relative positions of the Moon, Earth, and Sun. When the Earth is between the Moon and the Sun, it casts a shadow on the Moon, causing a lunar eclipse and resulting in a 'new moon' appearance. This phenomenon is explained by the relative motions and positions of these celestial bodies."
    },
    {
      "key": "Reflective Surface",
      "description": "The visible face of the Moon comes from the sunlight it reflects. The different amounts of the Moon's surface that are directly illuminated by the Sun at different times cause the various phases. This is a result of the Moon's orbit around the Earth and its rotational alignment with the Sun."
    },
    {
      "key": "Elliptical Orbit",
      "description": "The Moon's elliptical orbit around the Earth also contributes to its appearance of waning and waxing. When the Moon is closer to Earth, it appears larger and brighter; when it is further away, it appears smaller and dimmer. This orbital eccentricity affects the timing and visibility of the different phases."
    }
  ],
  "endingNote": "CCD"
}
assistant