@ǝʇɐןoɔoɥƆ Thanks for the answer, but I am a bit confused. It seems like teiru can go after transitive verbs as well, and verbs that can have tearu after it too. So as I said above もう送っって can have both iru and aru following it. I know が ~ てある is used for when describing objects found in a scene, but besides that I don't know when else you would use it.

In ending sentences why do people end a の?

@user25750 From what I know it can be used at the end of questions as a softer か, or in feminine speech with non question sentences. There is also the のだ explanative which is means ~it is that = ～ のだ