Edward Foster is a building contractor. He and his customer have agreed that he will submit a bill to them when he is $25$ percent complete, $50$ percent complete, $75$ percent complete, and $100$ percent complete. For example, he has a $$200,000$ room addition. When he has completed $25$ percent, he will bill his customer $$50,000.$ The problem occurs when he is $40$ percent complete, has incurred expenses but cannot yet bill his customer. How can his revenue and expenses match? Discuss several ways that Edward's accountant could solve this problem. What accounts would be used?