sentence: Public transport means such as trains , planes and buses are known as the cheapest and are used by all travelers , and the cost of using them is something that suits people who earn not much money ,
modified: Public transport means such are trains , planes and buses are known as the most cheap and used by all travelers , and the coast of using them is something that suits the people who earn not so much money .
transformation: OTHER, ADJ:FORM, VERB:TENSE, NOUN, DET, ADV, PUNCT