【单选题】Training a dog to be a watchdog often reduces unexpected results. Some dogs quickly learn the difference between unwanted people and friends. This is because their masters welcome friends into their...
A.
Training a dog to be a watchdog often reduces unexpected results.
B.
Some dogs quickly learn the difference between unwanted people and friends.
C.
Some dogs will always attack the postman who comes to deliver letters.
D.
The dog thinks the postman is someone not wanted, but keeps coming back anyway.
【单选题】Read the passage and choose the correct answer.Jimmy has been a postman for the last ten years. He loves to talk to his wife in the evenings about the people he delivers to. He tells her about Mrs. Ma...