in a jerk

基本解释

For example, the guy who cut you off in traffic is a jerk and an idiot.
例如，让你在路上受重伤的家伙是个白痴和傻瓜。
In a jerk the goat in tiger skin shivered with fear. Even the hesitant jackal which had stopped its steps was baffled.
披着虎皮的山羊猛地吓得浑身颤抖起来，连那只已停下脚步迟疑不前的豺狼都有些莫名其妙。
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The underrated Spielberg movie AI asked this question in a tear-jerk way from the point of view of an extremely realistic robot boy – a modern Pinocchio.
斯皮尔伯格那部被低评的电影《人工智能》通过一个极其真实的机器男孩——现代版的皮诺曹——的视角，以一种催人泪下的形式问出了这个问题。

Expect a Romney victory to spur short-term dollar strength, which could come in tandem with a knee-jerk rally in equities.
FORBES: A Romney Victory Will Send The U.S. Dollar And Equities Higher, But Only In The Short Term, Nomura Says
In a knee-jerk reaction there will be a call to ban or curtail the activities of these devils even though the report does not conclude that speculators were the cause for the run up in gasoline prices.
FORBES: Briefing Book: A. Michael Lipper
So we shouldn't be spooked by this notion that, well, is now the time to take seriously in an intelligent way, not in a knee-jerk way, the challenge of financial regulatory reform so that you don't have banks that are too big to fail and you're not putting taxpayers at risk and you're not putting the economy at risk -- now is the time to do it.
WHITEHOUSE: President Obama Takes Questions from Senate Democrats