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English Reference for kankeidaimeishi (かんけいだいめいし)
Relative pronouns perform as 'conjunction + pronoun'
However, the preposition+relative pronoun (which) part becomes a relative adverb (where)
The relative pronoun 'that' has two states, a nominative case and objective case, but there is no possessive case
The problem quoted isn't one, but there are problems in the reading section that ask you to distinguish relative pronouns from relative adverbs