A、He didn’t consult a car expert. B、He didn’t bargain like an expert. C、He didn’t check the engine carefully. D、He focused only

W: John, do you like to go swimming at the pool with me today? I’m afraid I dare not swim alone.
M: Sure, but I can’t leave yet. I’ve lost my room key and I have to wait for the security guard to let me back into my room.
Q: What is John’s problem?

M: It was embarrassing. I was only looking at the exterior and neglected the engine, which should be the priority when it comes to second-hand vehicles, I even thought I’d bargained like an expert.
W: Well, just think of it this way. You paid for your lesson on cars.
Q: What was the man’s major mistake when he bought the car?