be or come into a cluster or close group; congregate. "the children clustered around her skirts"
noun [具体名词] 聚集，收集；分类归并；聚类装饰（房间装饰）
...clusters of men in formal clothes. … 几组身着正装的男人。
verb [vt. 及物动词] 使成群（cluster 的现在分词）
The passengers clustered together in small groups. 乘客们聚集成小群体。
