sentence: To sum up , no one knows the future . However , I believe that travelling on public transport is as convenient as by car or more so , because it is good to save money and to reduce pollution .
modified: To sum up , no one knows the future ; however , I believe that travelling on public transport is as convenient as by car or more because it is good to save up money and to reduce contamination .
transformation: PUNCT, OTHER, PART, NOUN