题目

  It's the end of class. When the bell rings, students of Luohu Foreign Languages School in Shenzhen quickly take out their cell phones. They want to log on to their micro blogs to check the interesting things that have happened in the last hour. Since last year, the trend（潮流） of micro blogging has swept the country. Recent surveys shows that most students in middle schools have a micro blog and some even update（更新） their blogs over five times per day. We learn many fresh and interesting things on micro blogs and they have become popular topics in class, said Andy Liang,下列图形中能折叠成三棱柱的是（　　） A、B、C、D、