EOS CPU: on EOS, the CPU represents processing time. It is a scarce resource, which is often not enough. The CPU needs to be secured by EOS, or you can ask a friend to mortgage the EOS to send you the CPU. After using up, you can redeem the EOS, but the redemption requires a three-day waiting period.
EOS NET: network bandwidth represents the throughput of the EOS blockchain. Not to mention the scarce resources, there is almost no shortage of the situation. NET needs to be obtained with EOS mortgage. Like CPU, redemption requires a three-day waiting period. Here's how the EOS network keeps transactions free.
EOS Ram: commonly translated as Memory, full name is the abbreviation of Random Access Memory. Large amounts of data on EOS are stored in RAM. It is the scarcest systematic resource that must be acquired by purchase.