Until recently, almost everyone thought that growth and progress would make the world a 61.____ (good) place. They believed that something new was always better than something old. So countries have spent billions of dollars . 62_____ science to develop new ways of making things and doing work. 63_____ , this new technique is the main cause of the world’s problems. One such problem has come from the 64._____ (appear) of the car. In some 65.______ (crowd) cities, the car has polluted the air 66._____ badly that people get sick just from breathing it