Combine yeast, sugar and lukewarm water in a bowl. Leave aside for 10 minutes until mixture turns frothy.
Sift flour and salt in a mixing bowl. Make a well in the centre and pour in yeast liquid. Stir in milk, water and oil.
Mix into a dough. Knead dough for 15 to 20 minutes, adding more flour if necessary. When dough is smooth and elastic, shape into a ball.
Place dough in an oiled bowl and brush top with a little olive oil. Stand in a warm place for one to one and a half hours or until double in bulk or size.
Knock down dough and place on a floured surface. Knead gently and divide into equal portions. Knead each portion into a ball and place on a lightly floured tray.
Cover with a clean tea-towel and stand in a warm place for 30 minutes or until double in size.
Preheat oven to very hot (or highest setting). Roll each ball into a 25cm round. Heat a baking tray in the hot oven and place one round dough onto the hot tray, bake for about four to five minutes or until it puffs up. Turn over quickly and cook the other side for one minute to brown.
Remove from oven and wrap cooked pita bread in a clean tea towel to keep warm.