Simplify the following text for a Grade 4 native English-speaking person.
Original: According to the Biography of Cao Man , Cao 's uncle often complained to Cao Song about Cao Cao 's indulgence in hunting and music with Yuan Shao . In retaliation , Cao Cao feigned a fit before his uncle one day , who immediately rushed to inform Cao Song .
Simplified: Cao Cao ( æ æ `` 155-220 ) was a Chinese general .