The “Knocking on Wood” Wikipedia page mentions Roud’s conclusion, and this claim of a 19th century origin has circulated online as the final say on the matter. If you go back to the original, though, Roud’s proposal actually ends on an ambivalent note: “Before this theory [of 19th century origins] can be finally accepted, however, an examination of the history of European forms of this custom would be advisable.”
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Be the first to know!，这一点在夫子中也有详细论述
他還引導我參考美國國防語言學院的外語中心（US Defense Language Institute's Foreign Language Center），那裡提供當今最密集的語言訓練之一。從波斯語到日語，即使每天上課多達七小時、再加上課後作業，也需要大約 64 週才能達到基本專業熟練度。