这个帖子有点问题。当时忽略了watch是非终结性持续动词。所以例子举得不够恰当。现在更正如下：

非终结性持续动词的过去分词只表示被动意义，不表示完成意义。所以作状语的时候，being done形式和done形式的意义相同。所以：

Being watched by so many people, she felt very nervous. 现在分词被动语态作状语

= Watched by so many people, she felt very nervous. 过去分词作状语（没有完成意义）

终结性持续动词的过去分词表示被动和完成双重意义，如果被动动作没有完成，还在进行，则要用现在分词被动语态。

Built on top of the hill, the house looks very beautiful. 房子是盖好的

Being built on top of the hill, the house already showed the sign of magnificance. 房子正在建造。

下句中的being不可省略，否则逻辑错误：

HIs house being repaired, he has to stay at a hotel.