This paper continues the work on Ricci flow with surgery on three-manifolds, verifying most of the assertions from section 13 of the previous paper. It addresses the issue of collapsing three-manifolds with local lower bounds on sectional curvature, which is deferred to a separate paper. The paper also corrects an unjustified statement in Hamilton's work and clarifies the lower bound for volumes of maximal horns and smoothness of solutions. The paper introduces the concept of ε-necks, ε-horns, and ε-caps, which are important in understanding the structure of solutions to the Ricci flow. It discusses ancient solutions with bounded entropy, showing that such solutions are either κ-solutions or metric quotients of the round 3-sphere. The paper also constructs the standard solution, which is rotationally symmetric and converges to the standard solution on the round infinite cylinder. The paper then analyzes the structure of solutions at the first singular time, showing that the manifold can be reconstructed by gluing together components of the solution. It discusses the Ricci flow with cutoff, where surgeries are performed to remove singularities. The paper justifies the canonical neighborhood assumption, showing that solutions with cutoff satisfy the necessary conditions for the Ricci flow to be well-defined. The paper also addresses the long-time behavior of solutions, showing that if the initial data has positive scalar curvature, the solution becomes extinct in finite time and the manifold is diffeomorphic to a connected sum of spheres and metric quotients of the round 3-sphere. If the scalar curvature is nonnegative, the solution becomes positive unless it is flat. If the scalar curvature is negative, further analysis is required to understand the long-time behavior of the solution. The paper also corrects an error in a previous theorem and provides a proposition that supports the analysis of solutions with cutoff.This paper continues the work on Ricci flow with surgery on three-manifolds, verifying most of the assertions from section 13 of the previous paper. It addresses the issue of collapsing three-manifolds with local lower bounds on sectional curvature, which is deferred to a separate paper. The paper also corrects an unjustified statement in Hamilton's work and clarifies the lower bound for volumes of maximal horns and smoothness of solutions. The paper introduces the concept of ε-necks, ε-horns, and ε-caps, which are important in understanding the structure of solutions to the Ricci flow. It discusses ancient solutions with bounded entropy, showing that such solutions are either κ-solutions or metric quotients of the round 3-sphere. The paper also constructs the standard solution, which is rotationally symmetric and converges to the standard solution on the round infinite cylinder. The paper then analyzes the structure of solutions at the first singular time, showing that the manifold can be reconstructed by gluing together components of the solution. It discusses the Ricci flow with cutoff, where surgeries are performed to remove singularities. The paper justifies the canonical neighborhood assumption, showing that solutions with cutoff satisfy the necessary conditions for the Ricci flow to be well-defined. The paper also addresses the long-time behavior of solutions, showing that if the initial data has positive scalar curvature, the solution becomes extinct in finite time and the manifold is diffeomorphic to a connected sum of spheres and metric quotients of the round 3-sphere. If the scalar curvature is nonnegative, the solution becomes positive unless it is flat. If the scalar curvature is negative, further analysis is required to understand the long-time behavior of the solution. The paper also corrects an error in a previous theorem and provides a proposition that supports the analysis of solutions with cutoff.