Go to the bottom of the class!

I did English to A-level and have always thought of myself as pretty literate, but having seen a few questions from the exam which apparently 11-years olds have to sit, I'm now not too sure.  It seems there are things called "determiners", which is something I have never heard of, and how about this question - "My baby brother was born in the hospital where my father works, What is the phrase 'where my father works' in that sentence"?  Well, for starters, it's not a phrase - there's a verb in it (works) so it's a clause.  What does it do? It describes, or tells us more about "hospital".  Hospital is a noun, and a word which describes a noun is an adjective - so it's an adjectival clause.  Wrong answer, apparently - it's a "relative clause". Another description I have never heard before. So I would fail miserably.