2 Some people put the letters into boxes for different towns.3 Some people put postmarks to the letters. 4The postman takes the letters to the sorting office.5 A machine sorts the letters from the parcels.6 The letters go to different towns by train. 7 The postman delivers the letters.По-моему, это не для 3 класса, а проверка работников почтслужбы на профпригодность))