Describe an occasion when you were not allowed to use your mobile phone

The clearest example was during my final school examinations, when phones had to be left in a box at the front of the hall for three hours at a time. It sounds trivial now, but on the first morning I found it genuinely unsettling — I kept reaching for a pocket that was empty. The rule was strict because a few students in another province had been caught photographing papers the year before, so the invigilators collected everything before we even sat down. For the first twenty minutes I was more aware of not having my phone than of the exam in front of me. After that, something shifted. I actually concentrated better than I had in any practice test at home, where I'd check messages every ten minutes without noticing. By the third exam I stopped thinking about it altogether. Looking back, I'm oddly grateful for that rule. It was the first time I'd been separated from my phone for hours without choosing to be, and it showed me how much of my attention I was giving away by default. I've since started leaving it in another room when I study — deliberately recreating the same conditions.