instrumental/ɪnstrʊˈment(ə)l/
adj.1. 有帮助的;有作用的to be instrumental有助于…
Technical innovation is instrumental in improving the qualities of products.技术革新有助于提高产品的质量。
The neighbours were instrumental in catching the criminal.邻居们发挥了作用帮助捉拿了那个罪犯。
2. 为乐器演奏而作的instrumental music器乐