fail 动词 fail in sth在...方面失败
fail to do sth忘记/没能做成某事
failure 不可数名词 "失败"
可数名词 "失败的人/事"
eg:He failed in the exam.
He failed to get there on time.
Success is the mother of success.
He is a failure as a father.
*our collective failure to make hard choices and prepare the nation for a new age中our后面要加名词,所以用了名词failure
(failure后面的不定式是作定语的,修饰failure)