I was just looking for a little bit of a clarification, as some of the flash cards at the end of the lesson brought up a few questions. I understand that you can て あります and て います along with a Transitive and Intransitive verb respectively to show a change in state.
While doing the tests at the end an example would prompt something along the lines of “The lights turned on." which to me seems like a clear change in state. There is no evidence of human intervention, so I should use the Intransitive 付く and use the て います to show the change in state. My answer would have been
電気 が 付いて います。
However in many cases it seems like they were looking for the polite past tense of the verb.
電気 が 付きました。
I felt like for many of the questions at the end of the lesson I found myself saying “The answer is X, or Y” and I was wondering if both are correct ways of interpreting the information given, and when one is appropriate and not the other.
Thank you very much for your patience and understanding.