He hurried to the airport,only to find the plane had taken off/

问题描述:

He hurried to the airport,only to find the plane had taken off/
这里用only to find 不定式有什么作用?

only to do表示努力去做某事但结果却是令人丧气的,一般都翻译为"结果却是..."
这句句子的意思就是: 他急吼吼赶到机场结果却发现飞机已经飞走了