He nested the cottages in clusters, at different levels on the mountainside.他在一层层的山坡上盖建了一簇簇的小别墅群。People stood in clusters around the noticeboards.人们聚集在通告栏前。Most galaxies are found in clusters rather than in isolation.大多数星系都成星团存在，而不是孤立的。Grapefruit grow in clusters.葡萄柚是成簇生长的。