wild goose chase

n. 徒劳的搜索(劳而功的事)

例句与用法：

The reporter was sent on a wild goose chase, for the monster he was to investigate had never really existed.

记者被派了去作徒劳无益的调查，因为他要查寻的怪物根本不存在。

详细释义：

ph.

白费力气的追求; 徒劳之举