When you were brimming with confidence after studying classical physics and ready to achieve great things, only to be told that they are just approximate theories under a low-speed macroscopic weak gravitational field would you feel? This article will calm down your false alarm, make you believe that classical physics remains precisely applicable under high-speed strong gravitational fields (the microscopic situation will be discussed separately) , itself is sufficient to precisely solve issues such as the gravitational bending of light, the perihelion precession of planets due to spacetime curvature, radar echo delay, quasars, dark energy, and dark matter. The evolution of physics to the stage of quantitative analysis was made possible by the introduction of a coordinate system. By Einstein's era, observational coordinate systems and background coordinate systems can no longer share the same coordinate system, abbreviated as NSCS (The Newtonian era corresponding to the shared coordinate system, abbreviated as SCS. The same below). At this point, the primary issue in the NSCS stage becomes which coordinate system the observer should use to measure and read the spacetime data of the observed object. Cling to traditional concepts, choosing the observer's coordinate system as the reading coordinate system, naturally leads to the conclusion that classical physics is an approximate theory. This article chooses to follow the natural law of that only the background coordinate system can serve as the reading data coordinate system, resulted in a theoretical framework based on that 'Two Rules of the data measurement and the reference frame duality, four-sames of the laws of spacetime evolution, and one-strategy of using linear solve nonlinear'. Within this framework, classical physics remains accurate, user friendly, and sufficient. A series of examples listed in this article can serve as proofs.