another change in our life is that transportation becomes easier. I remember my grandfather has told me that when he was a student, he had to walk 10 km to go to his high school, because few people had a bicycle, not mention a car. However, the situation has changed now. If you want to go somewhere in a city, we have many choices such as a car or a bus, and they are very fast. Although we might be stuck in a traffic jam, in generally, it is still faster than using feet. Besides, the development of train and airplane also make the long-distance trip easier than the past. For example, in the past, most people would choice a ship as they went to American; it would cost them several months. Today we can finish the trip by airplane in only one day.