a cluster of stars的用法和样例：
- A cluster of stars smaller than a constellation.
- They resolved a cluster of stars with a high-powered telescope.
- A cluster of stars in the constellation Taurus, the five brightest of which form a V, supposed by ancient astronomers to indicate rain when they rose with the sun.
- There was a cluster of fans around the actor.
- He found a cluster of mushrooms in the forest.