1 b Complete the sentences. Marta is Alvaro's sister. 1 Alvaro is __________ brother. 2 Cecilia is __________ sister-in-law. 3 Eduardo is Cecilia's __________. 4 Marta is Manuel's __________. 5 Marta, Pedro and Alvaro are Cecilia's __________. 6 Pedro is Eduardo's __________. 7 Marcela is __________ mother-in-law. 8 Juan is Alvaro's __________. 9 __________ is Marta's father.