1, The fish are dead because of polluted water

2, Too much carbon dioxide in the atmosphere cause global warning

3, Oil spill in oceans and rivers leads to the death of many aquatic animals and plants

4, If teachers don't teach environmental issue at school, students won't be more aware of protecting the environment,

5, If she didn't work in a noisy office, she wouldn't have a headache after work every day

6, Vy had a stomachache since she ate a big dinner

7, If people don't throw rubbish in the streets, the streets will look attractive

III

1, are- will_ do

2, will be -plant

3, will save- don't waste