Unit 21. Relative clause

21.1 The theory of relative clause

21.2 Make one sentence from two using relative clause

21.3 Complete the sentence with the right part of a sentence

21.4 Choose the correct option (A or B), or fill in the blank with the appropriate relative pronoun and punctuation. Decide whether the clause is defining or non-defining based on context.

21.5 Choose the correct option or complete the sentence using the appropriate relative word and punctuation