sentence: Nowadays , the use of vehicles powered by gasoline and diesel is the main cause of air pollution in big cities around the world . Research shows that private cars are used , most often carrying a small number of people at a time , which makes it very inefficient considering the quantity of carbon dioxide and other toxic substances emitted into the environment each time the engine is started .
modified: Nowadays , the use of vehicles powered by gasoline and diesel is the main cause of air pollution in big cities around the world . Researches show that the private cars are used most often carrying few person at a time , what makes it very inefficient considering the quantity of carbon dioxide and other toxic substances expelled to the environment each time that the engine is started .
transformation: MORPH, VERB:SVA, DET, PUNCT, OTHER, PRON, VERB, PREP, PREP