What I found is that written evidence for knocking on wood (and for the history of gesture as a whole) is remarkably sparse. In the Penguin Guide to Superstitions, folklorist Steve Roud offers a skeptical take on the provenance of knocking on wood due to the near total absence of written records about it:
Explore more offers.，更多细节参见同城约会
Мощный удар Израиля по Ирану попал на видео09:41。关于这个话题，91视频提供了深入分析
This story was originally featured on Fortune.com
See sessions of two related sites as a single session