Nowadays, smart phone is a device which is popularly used by most people. It's not only necessary for many teenagers but it also has many advantages.

       Although it breaks easily, it has many good functions. Firstly, for communication, it helps you make phone calls and receive messages without meeting the people you need. Secondly, for entertainment, you can listen to music and play many interesting games. It helps you relax after tiring lessons. Finally, for information, you can surf the Internet when you have a difficult exercise. Besides, you can use maps to look for places when you get lost. 

       In short, smart phone is an useful thing for us. It provides many important things to our knownledge. Each of us should use it reasonably and efficiently.