... describe. relative pronoun is necessary relative pronoun is not necessary Relative clauses - defining or non-defining? Study the situations and then decide whether the following relative clauses ... Mary's Church which we visited yesterday is very old. St. Mary's Church, which we visited yesterday, is very old. Non-Defining Relative Clauses Combine the sentences using relative clauses. ... in Westminster Abbey. Samuel Johnson Relative Adverbs Choose the correct relative adverb. Exercises on relative clauses. I- Combine the two sentences using relative pronouns. 1. I apologizes to...