以下段落节选自课文,请仔细阅读,然后回答问题。 I sat down in a chair and pretended to read a book, but out of the corner of my eye I kept watching Petey. He was a torn man. First he looked at the coat with the expression of a waif at a bakery window. Then he turned away and set his jaw resolutely. Then he looked back at the coat, with even more longing in his face. Then he turned away, but with not so much resolution this time. Back and forth his head swiveled, desire waxing, resolution waning . Finally he didn't turn away at all; he just stood and stared with mad lust at the coat. (50) Question: How does the author vividly describe Petey in this part? What is his psychological movement?