《韦氏高级》将serve后接to do不定式用法归为不及物用法，不定式作结果状语。

: to have a particular result or effect — often + as

• Babysitting his nieces served as a test of his patience.

— often followed by to + verb

• She tried hard but her efforts only served to bring more attention to her lack of experience.

你如果查词典，你自己就能解决这个问题。