用所给词的适当形式填空。
1.A lot of plastic ______(be) bad for the earth.
2.Planting many trees can help us ______(keep) the air clean.
3.We should ______(eat) fruit and vegetables every day.
4.Please ______(not) waste water, Mike.
5.We can use the lift ______(go) up and down.
6.There are many plastic ______(bottle) on the table.
7.We use wood ______(make) chopsticks.
8.We shouldn’t ______(cut) down too many trees.