阅读下面材料，在空白处填入的内容（1个单词）或括号内单词的正确形式（不超过3个单词）。
Friends play an important part in our ____ (life). Though we may take friendship for granted, we often don't clearly understand ____ we make friends. While we get on ____(good) with many people, we are usually friends with only a few—for example, per student usually ____ (have) about 6 friends. In all the cases of friendly relationships, two people like one another and enjoy ____ (be) together. ____fact, as we get to know people, we take into account things like age, race, economic condition, social position, and intelligence. Although these things are not of great ____ (important), ____ is more difficult to get on with people when there is an obvious difference in age and background. Compared with marriage, there are no friendship ceremonies to ____ (strong) the connection between two people. But the mutual（彼此的）understanding that results from common experiences and emotions does seem to create a powerful bond, ____ can overcome difference in background, and break down barriers（障碍）of age, class and race.
，这个多边形的边数为（ ）
