(一)  Have you ever heard flash mobs?  By getting into touch with each other on the Internet, flash mobs do interesting things together.  The leader, who makes the plans, will tell everybody in the group when they are going to meet, and what they are going to do.  They usually wear clothes of the same color and show up in a public place, like a train station, and do something unusual.  Flash mobs stay in a place for only a few seconds and then leave.
　　Joining flash mobs is a way for people who meet on the Internet to do something creative and get to know each other at the same time.  Some people find flash mops annoying, but most people there are just trying to have some fun.

flash mob 快閃族   annoying 令人討厭的