Replace the of of of phrases by the noun in the Possessive Case: 1. The wife of Doctor...

Question

Replace the of of of phrases by the noun in the Possessive Case: 1. The wife of Doctor Sandford. 2. The elder sister of Helen. 3. The friend of my brotherinlaw. Помогите пожалуйста

Answer 1

Doctor Sanford's wife
Helen's elder sister
my brother-in-law's friend