Contractors has to be bonded

"contractor拿了钱，活干了一小部分，宣布破产"

https://www.investopedia.com/terms/p/performancebond.asp#:~:text=A%20performance%20bond%20is%20issued,obligations%20specified%20in%20the%20contract.&text=A%20performance%20bond%20is%20usually,a%20contractor%20completes%20designated%20projects.

What Is a Performance Bond?

A performance bond is issued to one party of a contract as a guarantee against the failure of the other party to meet obligations specified in the contract. It is also referred to as a contract bond. A performance bond is usually provided by a bank or an insurance company to make sure a contractor completes designated projects.