By installing special electric pumps, farmers’ houses could be heated

phoenix2194

Typically, preposition + -ing forms an adverbial modifier, so it can certainly modify an entire clause. Even plain -ing words are often adverbial modifiers. When you have one of these modifiers at the beginning of a sentence, it does not necessarily modify the following noun. The issue is that it has to make sense modifying the clause, and the first noun is typically the subject of the sentence.

In this case, "by installing pumps" definitely modifies the entire clause. But who is performing that action? Farmers. So we need to make sure that farmers are the subject of the clause. Let's look at two examples that do NOT work:

Wanting to impress my girlfriend's parents, my blue suit was the perfect choice.

The initial modifier needs to modify the clause that follows. It's situating an action: what happened when someone wanted to impress their girlfriend's parents? Wait, now we're talking about a suit? I don't think a suit can have a girlfriend! If we had any doubt, we could look at the verb: "was." "Wanting to impress" does not modify how/why the suit was a good choice. It modifies why I wore the suit.

Correction: Wanting to impress my girlfriend's parents, I wore my blue suit.

Now what about this?

By failing the test, Jim was forced to repeat the course.

If we read the initial modifier as modifying "Jim," all seems fine. But "By failing the test" doesn't make sense as a noun modifier. It's not adding detail about who Jim is, for instance. It should be introducing what happened as a result of his failure. This still might seem fine. The result is that he was forced to repeat. But the two don't work together. He wasn't forced to repeat by failing. Even though the initial modifier is adverbial, it needs to match up with a clause performed by the person who failed.

We can't really correct this one with the current modifier. There's nothing JIM did by failing the test, unless we want something like this: "By failing the test, Jim doomed himself to repeat the course." In this case, it would be easier to turn the first part into a dependent clause: "Because he failed the test, Jim was forced to repeat the course." Since these are two clauses, the first does not modify the second; they just have to make sense as a cause-effect pair.

Short version: If you see an initial modifier, it may be a noun modifier or adverbial modifier. However, in either case it will have to make sense with the subject that follows. Also, preposition + -ing will typically form an adverbial. (Almost every such rule has an exception, but I can't think of a way to make a noun modifier in that form.)

Here's a good official q that tests this concept: https://gmatclub.com/forum/defense-atto ... tml#p54047