第1个回答 2022-11-28
回答如下：
之所以用speaking是因为句子需要它作状语、宾语、表语、定语、主语等。speaking of something中的speaking既是动名词，也是现在分词。动名词和现在分词用法不尽相同：动名词可以作主语、宾语、表语、定语和同位语;现在分词可以作状语、表语、定语、宾补。试比较：
I don't mind your speaking(动名词) of pollution.
Speaking of pollution(时间状语), the villager was very excited.
My aim is speaking (动名词)of pollution.