徒勞 angolul

wild-goose chase▼(fruitless, futile pursuit)
noun
[UK: waɪld ɡuːs tʃeɪs] [US: ˈwaɪld ˈɡuːs ˈtʃeɪs]

in vain▼(without success)
adverb
[UK: ɪn veɪn] [US: ɪn ˈveɪn]