People leave missed calls all the time: If you're running late for a meeting and you just want to let them know that you're on the way, you leave them a missed call.
人们时时刻刻都在利用未接来电： 如果你要参加一场会议， 眼看着就要迟到了， 想让他们知道你在路上， 给他们一个未接来电就好了。