expose a fraud的用法和样例：
- This hair-tonic is a fraud; I'm as bald as ever.
- The reporter was killed because he tried to expose a plot.
- An act of cheating; a fraud or swindle.
- This woman is a fraud she has no medical qualifications at all.
- He said he was an insurance salesman but later she realized he was a fraud.
- He's nothing but a liar and a fraud.