That is, according to online lyrics. Except in this video, both at 00:25-00:26 and at 1:18-1:20, I hear:
Ta kan yi yan
So are the lyrics wrong, or is it me mishearing, perhaps its /thau/ with the /u/ being almost undetectable, and that is some regional/dialectal pronunciation? How should it be spelt if "Ta kan yi yan" actually makes sense?
While browsing Youku to respond to @dan's comment with a Youku video, I found this, where the line is:
That certainly matches the sounds I hear, but what does it mean?