fail to do sth.沒有,不能
fail in（doing）sth.在……方面失敗
例如：
I fail to see why you find it so amusing.我弄不懂你們?yōu)槭裁磳?duì)這件事感到如此好笑.
He never fails to phone his mother on her birthday.每逢母親過生日時(shí),他都會(huì)打電話給她.
The chairman failed in trying to persuade the committee to share his opinion.主席未能說服委員會(huì)同意他的觀點(diǎn).
He has been failing in health for the last two years.近兩年來,他的健康狀況一直在衰退.
fail in sth 和fail st用不能直接用