14.On ___ (introduce) to somebody,a British person often sha

14.On ___ (introduce) to somebody,a British person often shakes hands with the stranger.
填什么,怎么分析?
答案是being introduced 是victorgc 原来写的那样！

introducing
介词后,应该将动词的形式变为-ing形式,也就是我们所说的名词化