sentence: Firstly , it is very good for the environment because it reduces a lot of carbon dioxide gas which , if everybody took their car instead of taking public transport , would pollute the atmosphere .
modified: Firstly , it is very good for the environment because it reduces a lot of carbon dioxide gasses which if everybody took the car instead of taking public transport would pollute the atmosphere
transformation: NOUN:NUM, PUNCT, DET, PUNCT, PUNCT