sentence: Maybe travelling by car is so much more convenient , but there are a lot of cars and those cars produce a lot of fumes and the natural world is dying . If we do nothing , the natural world will disappear .
modified: Maybe travelling by car is so much more convenient , but there are a lot of cars and this car produce a lot of smoke and the nature is dying , if we do nothing , the nature will disappear .
transformation: DET, NOUN:NUM, NOUN, OTHER, PUNCT, OTHER