counterfeit?

My Chinese tutor had an interesting lesson for me today. She told me that the 50 kuai bill that I had paid her with was counterfeit. When she went to the bank to deposit the money, they took it from her and destroyed it. The poor woman.

She apologized profusely on behalf the Chinese people. When I asked her that I might have gotten the bill accidentally, she was convinced that it was done on purpose. We then went over how to spot a counterfeit bill, along with watermarks, color-changing ink, and textures so even blind people can spot a fake. Unfortunately, none of those things help a dumb American.

So since now I'm out $6.25, I'm gonna start checking my 50s and 100s.