1 as far as we know, earth is the only planet that human can live 2 the field is covered with a thin layer of snow 3 there are too many cars in major cities that polluted the air seriously. 4 children are protecting the mother-earth in their own way 5 even a smallest thing can make a big difference to the environment. 6 my father is paying attention to his weight now. 7.if you want to be sure to be healthy ,you need to take a good balance of diet. 8,aerobics is fit for everyone. 9,my grandparent are in good health and they travel from time to time. 10.the specialists comfirmed that walking is good for the health in many ways.