beats me

村上春樹の "Hear The Wind Sing" を読んでいます。
I wiped the dust off the windshield with a tissue while she slowly circled the car, eyeing it with suspicion. She stopped to stare at the big white bull’s head painted on the hood.
The bull had a huge ring through his nose and a white rose between his teeth. He was smiling a lewd smile.
“Did you paint that?”
“No, the previous owner did.”
“Why a bull?”
“Beats me.”
She took two steps back to study the bull some more, then got in the car with her lips clamped shut, as if regretting having talked too much.
"Beats me" はいかにも口語的な表現ですね。 "beat" を含む表現はこれまでにも幾つも取り上げました。
"my beats" (12/21/2015)
"If that don't beat all!" (9/15/2015)
"beat the odds" (3/30/2012)
"beat all" (10/5/2009)
さて "Beats me" の意味を調べます。
・McGraw-Hill Dictionary of American Idioms and Phrasal Verbs: I do not know the answer.; I cannot figure it out. The question has me stumped. (The stress is on me.) Bill: When are we supposed to go over to Tom's? Bill: Beats me. Sally: What's the largest river in the world? Bob: You got me beat.
・The American Heritage Dictionary of Idioms This baffles or puzzles me, as in I don't know how he does it-beats me! This term originally may have alluded to a winning poker hand. It may also be related to the even earlier usage of beat for "astonished" or "at a loss."
なるほど元は "it beats me" だったのですね。そしてアクセントは "me" にあるとは、実際に聴いて見たいですね。