sunbeam motor cars (2) actual income -- the increase of material wealth; Any transaction can be seen as a contract between the two parties. The so-called transaction cost can be seen as the cost of the transaction contract. According to Mr Coase and others, a type of transaction costs arise from the accidental factors that occur when a deal is signed. These incidental factors may not be written into the contract due to the fact that they could not be foreseen in advance, or although they could be foreseen, they could not be written into the contract due to too many factors. Another type of transaction costs is the signing of contracts and the cost of monitoring and enforcing contracts. According to the latest standard GB/T 3730.1-2001, cars are mainly divided into passenger cars and commercial vehicles. Mehrotra said the additional rate for PC flash drives in 2017 is about 35 percent, and will increase to 75 percent by 2020. And "a lot of hard drives still need to be replaced by SSDS... Future self-driving vehicles are expected to be equipped with about 40GB of DRAM... This will also drive the use of NAND flash memory." Consumption is up 3.1 per cent, according to mastercard, but online retailers are experiencing the best performance of the sales growth, up 12 per cent year on year. Although the supermarket's busiest day is expected to be Friday, card operators have found that spending on groceries has fallen by 0.1% so far. Planning is so important for the success of the transaction that it is necessary to use a hypothetical example to further illustrate.