Non-Defining Relative Clauses
Practice 1: Should these sentences have commas or not? Choose non-defining relative clause if you think it needs commas (the information is extra) and defining relative clause if you think it doesn't need commas (the information is necessary).
Practice 2: Who, which, that or nothing? Choose the best way to complete these sentences. Sometimes both answers are possible, so you should choose the last option - for example "the girl (who) I met yesterday is a rock star. ("who" is not necessary).