I asked OpenAI API that: What's the difference between saying "Arthur worked in a custom house" to "Arthur worked at a custom house"?
The device told me that: The difference between saying "Arthur worked in a custom house" and "Arthur worked at a custom house" is that the phrase "at a custom house" implies that Arthur was employed there, while "in a custom house" implies that he was present in the custom house, but not necessarily employed there.
I would like to know if it is real. I am trying to understand if OpenAI API is a trustworthy tool to learn English. Thank you.