Once upon a time, there was a man who loved money. He loved it so much that he wouldn't spend any of the money he earned. He wouldn't part with even a tiny bit.
This stingy man didn't buy new clothes. Instead, he wore old clothes that he found in the garbage. He didn't buy food, either, and he became skinnier and skinnier.
He put all the money that he saved in a box and hid it under his bed. Every night, he opened the box and looked at all his money.
One night, the man looked in the box and the money was gone! Someone had stolen it! "I've been robbed!" he shouted. "My precious money is gone!" He lay down on the bed and cried and cried.
The neighbors heard him and came over to see what was wrong. When they heard the story, one neighbor said, "Don't cry over your money. You never used it anyway. Fill the box with paper and imagine it is money. It will do you just as much good."
I spent one hundred dollars on my new watch.我花了一百美金买新手表。
He spent three days writing that report.他花了三天写那份报告。
Do （someone）good 对某人有益，有效用
Good 在此为名词，指利益，好处。 Do （someone）good指对某人有好处，主词常为事物。Good前面还可以加much，any等形容词来修饰程度。
It will do you to get out of the house more.多出去走走对你有益。