What are the differences between these three sentences?
I went to school and I ate my lunch in 3rd class.
I went to school and my lunch was eaten by me in 3rd class.
I had gone to school and ate my lunch in 3rd class.
Are these sentences correct? Are there any differences between the meanings of these sentences? If there are no differences, why might one sentence be used instead of another?
I know about the passive voice and the past perfect, but only enough to pass an English test. I don't have much practical experience.