📎 Grammar B1-31: Non-defining relative clauses

The thirty-first material of the Fleydo B1 grammar series picks up where Defining relative clauses left off and teaches the other kind: the clause that identifies nothing, because the sentence already knows exactly who it is talking about. The opening image is a whispered aside — My aunt Gwen, who lives in Lisbon, is arriving on Friday — and the delete test that proves it: lift the clause out and the same aunt is still arriving. Three rules guard the fence, and each gets its own formula line and trap: a pair of commas closes the aside off at both ends, that is banned completely between them, and nothing can be dropped — the pronoun-dropping trick from the defining clause dies at the first comma. A five-row table hands over the words that may enter the fence — who, which, whose, where — plus the B1 bonus move, which pointing at a whole event: The lunch lasted four hours, which nobody minded. The compare-and-verdict pair is the heart of the material: my brother who works at the bakery against my brother, who works at the bakery — identical words, and the commas alone decide how many brothers the writer has. A 124-word postcard from Lisbon makes every clause tappable, asides in green, identifying clauses in blue and event-which in orange. Practice runs to thirty-one explained multiple-choice items in four sets, twelve clause chips to sort into identifies and just adds, six real learner repairs and four traps. Teacher notes carry a 45-minute sequence, the count-the-brothers board move, the finger-over-the-clause rescue and Cambridge B1 Preliminary relevance.