for the life of one 成语
for the life of one|for|life
adv.,
informal No matter how hard you try.

Used for emphasis with negative statements.
I can't for the life of me remember his name.
for the life of one
for the life of one Although trying hard, as in
I can't for the life of me remember his name. This expression is always used hyperbolically, that is, one's life is not at all endangered. [Late 1700s]
for the activity of (one)
Despite one's best efforts; to any amount whatsoever. Often acclimated in abrogating constructions. For the activity of me, I can't bethink area I larboard my keys! She couldn't accept for the activity of her why bodies were so bedeviled with celebrity gossip.Learn more: life, offor the activity of one
Although aggravating hard, as in I can't for the activity of me bethink his name. This announcement is consistently acclimated hyperbolically, that is, one's activity is not at all endangered. [Late 1700s] Learn more: life, of, one
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