This song by Carrie Underwood is in two keys: C and D.
Towards the end, it is raised to E. Part 6 is the same as Part 3 in E key.
The chords in brackets are transitional.
These are the “cheat” chords I played…
Part 1a: C - Em - F - F/G - G/B
Part 1b: C - Em/A [...]
