Daily Chinese Idiom Guessing Game
A common sight; something so common that nobody finds it surprising.
司空古代官名。指某事常见，不足为奇。
唐·孟棨《本事诗·情感》载刘禹锡诗司空见惯浑闲事，断尽江南刺史肠。”
In big cities, seeing people glued to their phones is 司空见惯.