One of the more esoteric areas of grammar
The term nominal relative clause is not used very much in TEFL materials, even at advanced level. Nominal relatives and interrogative wh-clauses are usually simply treated together as wh-clauses.
But as one of my favourite student grammar books, Grammar and Vocabulary for Cambridge Advanced and Proficiency, by Side and Wellman (Longman), has one section on Nominal relative clauses, and another on (interrogative) wh-clauses, I thought it might be interesting to compare them.
I'd also noticed that a couple of learners had written to English language forums asking about the difference, so the question had obviously come up, at least for some people.
