Are you afraid of black cats?
你害怕黑猫吗？
Would you open an umbrella indoors?
你会在室内打开雨伞吗？
And how do you feel about the number 13?
你觉得数字13怎么样？
Whether or not you believe in them, you're probably familiar with a few of these superstitions.
不管你是否相信这些，你可能对其中一些迷信观念比较熟悉。
So how did it happen that people all over the world knock on wood or avoid stepping on sidewalk cracks?
那么，世界各地的人们是怎么会有敲木头或者避免踩人行道裂缝这些行为的呢？
Well, although they have no basis in science, many of these weirdly specific beliefs and practices do have equally weird and specific origins.
Because they involve supernatural causes, it's no surprise that many superstitions are based in religion.
For example, the number 13 was associated with the biblical Last Supper, where Jesus Christ dined with his 12 disciples just before being arrested and crucified.
The resulting idea that having 13 people at a table was bad luck eventually expanded into 13 being an unlucky number in general.
Now, this fear of the number 13, called triskaidekaphobia , is so common that many buildings around the world skip the 13th floor, with the numbers going straight from 12 to 14.
