Anyone could explain the difference between in which on which and at which?
And the usage in the sentences, please?

Question

Answer

Thank you for the explanation! Its getting clear now

Answer

Building on what Nicola said, imagine substituting 'which' for 'a'. It would not make sense to say "on a room", in should be "in a room", so we should say "in which".

You would get off 'at' a train station, so we would say "at which train station should I get off?" if we were asking someone where to get off.

Things are located on tables, "on a table", so you would say "on which table is it located?". It is the same for anything, if you are looking for something under a table it would be "under which table?".

Answer

Okay, here are a few examples: "in which room", "on which channel", "at which point".

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