Winning the scholarship was his main motivation to study hard.

motivation 是名词，来自动词 motivate（激励、促使）。motivate 由词根 mot（移动）和后缀 -ivate（使...）组成，字面意思是"使移动"，引申为"激励、推动"。 motivation 指"动机、动力"，表示促使某人做某事的内在驱动力或原因。