throwinthetowel(Ifyouthrowinthetowel,youstoptryingtodosomethingbecauseyourealizethatyoucannotsucceed.)认输
eg:Itseemedasifthepolicehadthrowninthetowelandwereabandoningtheinvestigation.
看起来好像警察已经认输了，并且要放弃调查。