我已是一个中年的人。I am already a middle-aged man.一到中年，就有许多不愉快的现象，眼睛昏花了，记忆力减退了，头发开始秃脱而且变白了，意兴，体力，什么都不如年青的时候，At middle age, I feel sad to find my eyesight and memory failing, my hair thinning and graying, and myself no longer mentally and physically as fit as when I was young常不禁会感觉到难以名言的寂寞的情味。. I often suffer from a nameless loniness.尤其觉得难堪的是知友的逐渐减少和疏远，缺乏交际上的温暖的慰藉。Most intolerable of all is the lack of friendly warmth and comfort due to the gradual passing away and estrangement of more and more old pals.
不消说，相识的人数是随了年龄增加的，Needless to say, the number of acquaintances increases with one’s age.一个人年龄越大，走过的地方当过的职务越多，相识的人理该越增加了。The older one gets, the morewidely traveled one is and the more work experience one has, the more acquaintances one is supposed to have.可是相识的人并不就是朋友。But not all acquaintances are friends.我们和许多人相识，或是因了事务关系，或是因了偶然的机缘——如在别人请客的时候同席吃过饭之类。We come to know many people either in the way of business or by mere chance –say, having been at the same table at a dinner party.见面时点头或握手，有事时走访或通信，口头上彼此也“朋友”，笔头上有时或称“仁兄”，诸如此类We may be on nodding or hand-shaking terms, call each other “friend”, sometimes write to each other with the salutation of “Dear So-and-So”, etc.,etc.，其实只是一种社交上的客套，和“顿首”“百拜”同是仪式的虚伪。All these are, in fact, nothing but civilities of social life, as hypocritical as the polite formula dunshou (kowtow) or baibai (a hundred greetings) used after the signature in old-fashioned Chinese letter-writing.这种交际可以说是社交，和真正的友谊相差似乎很远。We (加，被动）may call them social intercourse, but they seem to have very little in common with genuine friendship.
我用表情包标签了，这句话：We come to know many people either in the way of business or by mere chance –say, having been at the same table at a dinner party. 为什么chance后面的破折号 ，have变成doing了？是动名词做主语吗？我怎么理解不了，求大神解释