Sometimes you want to take the bus, or buy a drink from a vending machine, then you are looking for some change. If you see a big box of coins on the street, offering free cash for people in need. Would you take the money?
It has been touted as a social experiment on society, carried out in cities around the world. What are the test results? How has the reaction from some pedestrians surprised us?
n. 反应,反作用力,化学反应