Living in a modern society, the youth, especially is the students have to prepare three main things to be good citizens of the 21th century.Firstly, the knowledge is the most important one because people often say that “the things we know are just a drop of water. Things we do not know is an ocean.”That ‘s why it’s the key to open every field.Moreover, the people who have knowledge would have more chances than the ones who don’t.Besides, we also should study other languages like Japanese, English, Chinese,…as much as we could.As far as I know, English is considered as an international language in the world.It’s very easy for us to have a good position in our career path with good salary in the companies in future.Besides, learning English well also helps us approach the human’s knowledge easier.Secondly, the health plays an important role because a person who has a good health can put through a large amount of work in a short time.Furthermore, with the development of entertainment industry, there are so many useful games that can help us improve not only physically but also mentally.Let’s stay away from social evils, instead, let’s find reliable entertainment sources to have a better result.We should play soccer, baseball, badminton,…or read books and listen to music. They are the best choice after many hard-working hours at school.Last but not least, the social skill should be prepared as fast as possible when we are still studying in junior or high schools.Why don’t we take part in organizations and clubs? They are all the great environment for us to enhance self-confidence, communicative skills,…No matter how much knowledge we have, without the social skill, it’s really a big barrier on the trace to success.To sum up, I think that with three preparations above, students can easy to catch up with the new era of the 21th century, each of us should prepare them to have a brighter future.Living in a modern society, the youth, especially is the students have to prepare three main things to be good citizens of the 21th century.Firstly, the knowledge is the most important one because people often say that “the things we know are just a drop of water. Things we do not know is an ocean.”That ‘s why it’s the key to open every field.Moreover, the people who have knowledge would have more chances than the ones who don’t.Besides, we also should study other languages like Japanese, English, Chinese,…as much as we could.As far as I know, English is considered as an international language in the world.It’s very easy for us to have a good position in our career path with good salary in the companies in future.Besides, learning English well also helps us approach the human’s knowledge easier.Secondly, the health plays an important role because a person who has a good health can put through a large amount of work in a short time.Furthermore, with the development of entertainment industry, there are so many useful games that can help us improve not only physically but also mentally.Let’s stay away from social evils, instead, let’s find reliable entertainment sources to have a better result.We should play soccer, baseball, badminton,…or read books and listen to music. They are the best choice after many hard-working hours at school.Last but not least, the social skill should be prepared as fast as possible when we are still studying in junior or high schools.Why don’t we take part in organizations and clubs? They are all the great environment for us to enhance self-confidence, communicative skills,…No matter how much knowledge we have, without the social skill, it’s really a big barrier on the trace to success.To sum up, I think that with three preparations above, students can easy to catch up with the new era of 21st century, each of us should prepare them to have a brighter future.