a) automobiles b) bicycles c) airplanes

I think the development of airplanes has changed people's lives. Just before the development of airplanes, we can't go abroad easily. Although we can go another continent by train or ship, the airplanes make it more fast and safe. Also, It make us show other countries culture, and it is led us globalization. For example, In the Joseon Dynasty period, since it is take too much time and money, only rich people or trader can visit another country. So they aren't familiar with foreigner and foreign culture. However after the airplanes be ready for ordinary people, the trade is more active, so we can experience other countries technology and culture. That's why I think the development of airplanes has changed people's lives.

Hello there [이름]! ^^   Fantastic bang up job! ^^ Yes, I agree that airplanes have made traveling a whole lot easier and it\'s also a good thing there are things like economy flights for us less privileged people. ㅋㅋㅋ ^^ The thing to look our for though is the use of has and have. Remember: Has is used with the third person singular. For example: \"She has a great personality.\"Have is used with some pronouns and plural nouns: \"I have a great English teacher.\"   All good things, ==Teacher Charlie==     I think the development of airplanes has changed people\'s lives. >> I think the invention of airplanes have changed people\'s lives. Just before the development of airplanes, we can\'t go abroad easily. Although we can go another continent by train or ship, the airplanes make it more fast and safe. Also, It make us show other countries culture, and it is led us globalization.>> Before airplanes have been invented, we couldn\'t go abroad that easily. Even though, we can go to other continents by trains or ships, airplanes make it faster and safer and since traveling made us aware of other countries\' culture, it led to globalization. For example, In the Joseon Dynasty period, since it is take too much time and money, only rich people or trader can visit another country. So they aren\'t familiar with foreigner and foreign culture. However after the airplanes be ready for ordinary people, the trade is more active, so we can experience other countries technology and culture. >> For example, in the Joseoun dynasty, only the rich can visit other countries because they have the time and money. So most common people are not familiar with anything foreign. However, after airplane flights have been made available to ordinary people, trade has become more active, leading to experiencing other countries\' technology and culture. That\'s why I think the development of airplanes has changed people\'s lives. >> That\'s why I think the invention of airplanes have changed people\'s lives.