knock something on the headBritish EnglishBrE informalPREVENT to stop something happening 阻止某事发生 We wanted to go for a picnic, but the rain’s knocked that on the head. 我们原本打算去野餐，但是那场雨使计划泡汤了。
knock something on the head• Fortunately they didn't knock me on the head or anything which they could have done, couldn't they?
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