GMAT Sentence Correction (SC) | Re: This is a sentence from Manhattan SC After many years of

In adverbial modifications involving a comma and verb+ing, the clear rule is that it will modify the immediate previous clause's subject and its action. In the given context, the modified part is a deal and its action of lowering tariffs and ending subsidies. It There is no need to consider whether the previous clause is a relative clause or a subordinate clause or the main clause itself. All that one has to verify is what the previous clause is, what its subject is, and what the subject's action
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