The well water in this small village is enough to sustain the residents' daily needs.

sustain 是动词，由前缀 sus-（表示"在下面"）和词根 tain（来自拉丁语 tenere，意为"保持、持有"）组成，字面意思是"在下面支撑着"。引申为"维持、支撑、使持续"的意思，指提供必要的支持或资源使某事物能够持续存在或运作。