a lunar eclipse的用法和样例：
- It was reported that there would be a lunar eclipse tomorrow evening.
- Ancient people thought a lunar eclipse was a bad omen.
- Explanation: When a Full Moon lies near the ecliptic there can be a lunar eclipse.
- Shaped like a cone extending into space, the umbra has a circular cross section that can be most easily seen during a lunar eclipse.
- However, based on a lunar eclipse that Josephus reports shortly before the death of Herod the Great, the birth of Christ would have been some time before the year 4 BC/BCE.
- A lunar occultation of a quasar.