Due to financial constraints, we had to postpone the project.

constraints 是名词 constraint 的复数形式。constraint 由前缀 con-（表示"共同、一起"）和词根 strain（"拉紧、限制"）组成，意思是"限制、约束"。 financial constraints 指"财务上的限制"，即资金不足或预算有限的情况。