Dear shraddha,
I read your article on Verb-ing modifying preceding clause in case it is of the from of 'comma+verb-ing' and I am not really satisfied with the article.
How a single comma can make so many changes in a sentence ( comma+verb-ing modify preceding clause's subject). Verb- ing acts as subject modifier only if that verb-ing acts as adverbial modifier and is in complete tune with the context. I can give plenty of example where that verb-ing with comma acts as non essential modifier to the preceding noun. Have a look at this sentence --
On Tuesday, Mr. Ghani made a positive gesture by agreeing to Mr. Abdullah’s call for an audit of 7,100 polling places, encompassing more than three million ballots, and by urging unity.
Here, encompassing more than three million ballots acts as non essential modifier. Even general sentences such as -- President Obama called for radical reforms citing poor economic condition of country -- out-rightly violate your rules. Commas are used sometimes only to make thing clear, between adjectival and adverbial forms, I suppose.
Please help me out so that i could apply my ideas better in exam.
Neha