As the data clearly illustrates, the dominant reason is "Studying," which accounts for 59.50%, making it the majority. This is followed by "Killing time" at 20.50% and "Browsing for information" at 17%. The "Other purposes" category constitutes a minimal portion of only 2%.

Two main factors can explain this phenomenon. Firstly, the high percentage for studying reflects that smartphones have become an essential tool for academic work. Students use them to access e-books, search for academic materials, and complete assignments. Secondly, the significant portion for killing time suggests that phones also serve as a major source of entertainment, used for reading news or social media to relax during breaks.

In conclusion, the chart highlights the dual role of mobile phones in students' lives: as a vital assistant for learning and a convenient tool for leisure.