Hello, @PanQinhongCTR-9162!
The Azure Price Calculator makes visualizing this a lot easier. We can see from the Azure Spring Cloud pricing page that for the Basic tier, 2 vCPUs and 4 GB of memory are included. Your base price won't change regardless of how many hours you use as long as you stay within the limit of base vCPUs and base memory as this is a flat cost (1 hour would cost as much as 730):
20 Hours (2 vCPUs / 4 GB memory)
730 Hours (2 vCPUs / 4 GB memory)
Once you start adding additional vCPUs and memory above the included vCPU and memory for each tier, then you'll see an increased cost per hour (this shows up as vCPU overage and memory overage):
20 Hours (5 vCPUs / 10 GB memory)
730 Hours (5 vCPUs / 10 GB memory)