I'm trying to polish up on my grammar and am wondering when it is appropriate to use 'which' over 'that' in introducing relative clauses.
"I often buy cheese that is imported from Paris."
"I often buy cheese which is imported from Paris."
"He showed us how to create a computer game which was very interesting."
"He showed us how to create a computer game that was very interesting."
I attempted to search the forums but I'm afraid I don't know the English terminology enough to get past the 'simple word' filter. I couldn't find a way to phrase a question [which?/that?] would register.