请在下面的空格中填写合适的代词、连词或介词
There was a painter. He always wanted to be successful. _______ he was very poor, he never gave up painting and always stuck to his dream. He didn't do __________ except painting. However, ______ came to buy his paintings.
Sometimes he couldn't earn ________ money to pay for his meals. Luckily, the boss of the restaurant in the street where he lived was kind and let him have meals on credit.
One day, while the painter was having lunch in the restaurant, suddenly a great idea came to him. He immediately unfolded（打开） the white napkin（餐巾纸）on the table, took out his paintbrush, and began to paint with the dish left on the table. The boss couldn't stop him so he stood behind to watch him painting carefully. After a while, the painting was finished. Looking at his work, he thought ______ was the best he had ever painted.
The boss asked, "Could you please give _______ painting to me? Then you don't have to pay all ______ debts. Is that OK with you?" The painter was surprised. "You can also see this painting values a lot, right? Then I'm really not far away from being successful," he said happily. The boss replied, "Not really. Please don't misunderstand me. I mean, I have a son ______ always dreams of becoming a successful painter, just like _______. That's why I want to have it and warn my son not to end up like you."