Апостроф в данном случае означает принадлежность чего-то кому-то
Например:
Father's job - работа (чья?) отца
Sam's book - книга (чья?) Сэма и т.п.
Big - bigger
small - smaller
clean - cleaner
dirty - dirtier
comfortable - more comfortable
pleasant - more pleasant
industrial - more industrial
polluted - more poluted
safe - safer
crowded - more crowded
busy - busier
Do, after,at,to,sometimes
Клетка - cell
умный - clever
товарищ - companion
аквариум - aquarium
дружелюбный - friendly
трава - grass
семя - seed
Teddy's last holidays were very interesting. He was in Russia. He traveled there by plane,by train and by car. Yesterday morning I walked a lot in the park. There was no milk in the shop in the evening. In the summer we visited a lot of places in London. Did your sister played the piano when she was five? Did they helped their parents when they were on holidays?