Finishing the project report is one of my main responsibilities this week.

responsibilities 是名词 responsibility 的复数形式。responsibility 由词根 respond（回应、负责）和名词后缀 -ibility（表示"能力"或"状态"）组成，字面意思是"需要回应/负责的状态"，即"责任、职责"。 responsibilities 指"多项职责或责任"。