化简：$\frac{3x+6}{x^2+4x+4}$÷$\frac{x-2}{x+2}$﹣$\frac{1}{x-2}$．

根据短文理解完成下列各题。

    Mrs. Green had a young dog which was very clever. It often helped her buy a newspaper. One winter evening, the dog went out to play. It was snowing heavily. Soon the ground(地面) became white.

     “The dog never loses his way. Where is he now?” Mrs. Green thought. She shouted(喊) his name.

    But still the dog didn't come back. So she telephoned the police and told them a lot about her dog.

    “My dog is very clever. He always goes out and comes back soon. Sometimes he plays with his friend, Mickey. He can buy a newspaper. He almost talks.”

    The policeman was tired and said, “I think you'd better put your telephone down. Maybe he is trying to telephone you now.”

  ____  ____does Michael ride a bike?