Form the words as in the example. Example:the textbooks of the pupil - the pupils texetbooks 1) the nicknime of my sister - ... 2) the sharpener of his brother - ... 3) the fel - tip pens of their sons - ... 4) the computer of my parents - ...
1) My sister's nickname. 2) His brother's sharpener. 3) Their sons' fel-tip pens. 4) My parents' computer.