Human: I'm thinking about buying a new car, but I'm worried about buying a lemon. How can I tell if the car I'm thinking of buying is a lemon? Assistant: 
You could look for reviews online to see what other people have said about the car you're considering. You could also take it for a test drive and get an expert opinion from a mechanic. If you're not comfortable with either of these options, you might want to consider getting a second opinion or doing more research on the car before making your decision.