新概念3中的,on being observed,it immediately ran away.这个on doing 到底是什么结构呀?

新概念3中的,on being observed,it immediately ran away.这个on doing 到底是什么结构呀? 新概念3中的,on being observed,it immediately ran away.这个on doing 到底是什么结构呀? on its being observed, it immediately ran away.为什么用its?新概念3中的课后练习：___________, it immediately ran away.有两个正确答案：I. on being observed II. 或者替换成 on its being observed,问：II中的句子,为什么 新概念3第一课puma at a large课后的多项选择题中的结构题（新版的是17页）___________________it immediately ran away.a) Observing her b)On being observedc)Having been observed d) On her being observed选什么呢 原因? on being Being on On being introduced to somebody. 中的on being introduced是什麽时态什麽语态on being introduced 是短语吗? being 是什麽词的什麽形式 ,it immediately ran way.(新概念英语选择题）A：Observing her B:On being observed C:Having been observed D:On her being observed 新概念3课后习题6.It immediately ran away when she saw it=_______,it immediately ran away.(a)Observing her (b)On being observed (c)Having been observed (d) On her being observed 选B,为什么不选C?7.Pumas never attack a human being except __ On being told by being on my keep on being Being on sky.hovering. ON BEING CERTAIN怎么样 新概念英语上的问题._,it immediately ran away.a.Observing her b.On being observedc.Having been observed d.On her being observed这道题为什么选b?其他几个为什么不选? （）,it immediately ran away.A.on being observed B.having been observed这个为什么选A 我觉得B比较对.新概念第三册的第一篇 新概念英语3选择题He always insisted that it should be written out in full.He always insisted -------in full.a.on its being written out b.on writting it outc.to have it written out d.that it would have to be written out 为什么 the excitement of being on Mars is worth it 中要有being,没有不行吗?但我还有一个问题，例如：a feeling of being uncertain about something or not 中的being也是这个用法吗？