根据短文内容及首字母提示完成短文。（每空一词）
   Friends play an important part in our lives. We may have many friends, but we often don't understand c____how we make friends. We may get on well with a n____of people, but we usually make friends with a very few of them.
   People use the word "friend" freely. Friends may k____each other since childhood or they may recently meet. In fact, people many have different k____of friends such as school friends, work friends, or sports friends. A person may c____different friends for different activities. If you play with s____  on the playground, the person is your playmate. If you often play chess w____ a friend, the person is your chess partner.
   One may have many good friends and only one best friend. " Best friends" or "close friends" are u____two people who have known each other for a long time. A close friend is someone who is able to s____ experience, joys and sorrows(悲伤) with you. This is a person you can rely on (信赖) when you are in n____, and this is the person to whom you are willing to lend a helping hand.
   Friendship is one of life’s greatest treasure.

材料一：下图是甲国地图。甲国是美国重要的服装进口国，服装生产中心在A城；首都B城是该国重要的工业中心，纺织、食品、制糖是其主要工业部门。

材料二：2012年7月甲国决定修建沟通太平洋与加勒比海的水闸式运河。著名的巴拿马运河就是采用水闸来调整船只航行水位的。如下图所示，加通湖的湖水注入水闸，船由大西洋进入，依次经过1、2、3号水闸，上升至加通湖面，然后经过4、5、6号水闸，下降至太平洋洋面，完成航行。

材料一：

材料二：2017年7月30日，庆祝中国人民解放军建军90周年阅兵在朱日和联合训练基地隆重举行，***检阅部队并发表重要讲话，1万2千名受阅官兵、600多台受阅车辆装备集结列阵，犹如钢铁长城巍然屹立；100多架战机在6个机场整装编队。这是中国人民解放军首次以庆祝建军节为主题的盛大阅兵，是野战化、实战化的沙场点兵，是人民军队整体性、革命性变苹后的全新亮相。——《央视新闻))

材料三：***人深刻地认识到，苏俄式革命道路在中国行不通，经过艰难探索，***终于找到了“城市一农村一城市”的正确革命道路．取得了新民主主义革命的伟大胜利。

材料四：它不是一般意义上的“行军”，而是考验中国红军男女战士的意志、勇气和力量的人类伟大史诗，也是为避开蒋介石的魔爪而进行的一次生死攸关、征途漫长的撤退……