The Industrial Revolution, making it possible to mass-produce manufact

Hi NandishSS! Carolyn from Magoosh here I'll jump in and answer this for Mike!

This is definitely a big issue in GMAT SC, and one that comes up all the time. So, when we see an '-ed' verb/modifier, how can we tell which one it is? The answer is that we need to look at the context. Specifically, we need to first find the subject of the sentence, and think about the action associated with the '-ed' word. Then we ask ourselves: "Is the subject performing this action?" If the answer is yes, then the '-ed' word is a verb. If the answer is no, then it's a modifier Let's start with an easy sentence as an example!

The candle burned all night.

Here, the subject is "candle", and the '-ed' word that we're looking at is "burned". The action associated with this is "to burn". Here, it is clear that the subject (the candle) is doing the burning. So in this case, "burned" is a verb

The tablecloth, burned by the candle, now has a hole.

Here, we're still looking at "burned", but the subject is now the "tablecloth". So the question is - is the tablecloth doing the burning here? No - the candle is! So there's a mismatch - the subject of the sentence is not doing the action associated with the '-ed' word. That means that "burned" here is a modifier

Now let's look at our original sentence:

The Industrial Revolution, making possible the mass production of manufactured goods, marked by the use of new machines, new energy sources, and new basic materials.

The subject here is Industrial Revolution, and the '-ed' word we're looking at is "marked". Now, what's the action associated with "marked"? It would be "to mark" something. Is the Industrial Revolution doing the marking here? No - it is the new machines that are marking the Industrial Revolution. So we can safely conclude that "marked" here is a modifier.

Does that help clear this up? Let me know if you still have questions about this!

-Carolyn