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.”
为了测试这个新模型的理解极限，他随手甩出了一道极其刁钻的测试题：「给我画一张设定在古威尼斯的《寻找沃尔多（Where’s Waldo）》，但里面要找的不能是人，得是一只穿着蓝色条纹飞行服的水獭。」，更多细节参见PDF资料
。业内人士推荐新收录的资料作为进阶阅读
Путин прокомментировал рост цен на нефть и газ19:24
В Европе назвали причину паники Зеленского07:43，详情可参考新收录的资料