"赊购或赊销制度" can be translated into English as "the system of purchase or sale on credit".
Here, "purchase on credit" refers to buying goods or services with the agreement to pay for them at a later date, while "sale on credit" refers to selling goods or services with the same arrangement for the buyer. Together, they form the basis of the "赊购或赊销制度" (system of purchase or sale on credit), which is a common business practice allowing transactions to occur without immediate cash exchange.