请批改这段”鹦鹉学舌“， 谢谢！

Here are the lines:

1)         It was from an old school friend named Stephen Katz.

2)         Katz and I had grown up together in Iowa, but I had pretty well lost touch with him.

3)         "I've been hesitating to call," he said slowly. He seemed to be searching for words.

4)         "But this Appalachian trail deal, do you think maybe I could come with you?"

5)         I couldn't believe it. "You want to come with me?"

6)         "If it's a problem, I understand."

7)         "No," I said. "No, no, no. You're very welcome. You are extremely welcome."