In a typical interaction, a user quickly refers to his daily calendar or adds an item to his to-do list while sitting at a stop light. Cellular telephones are an interesting type of handheld device.

• 举个典型的例子，某人在等红绿灯时，使用手持设备快速地翻看了一下他的日历，之后在代办事项中添加了一条。