One of my favorite things to teach students about GRE verbal reasoning is how different parts of a passage function in relation to the whole because being able to identify the role of a part of a passage helps with comprehension of the whole. And comprehension of the whole is one of our goals in being able to answer questions.
Certain GRE questions will depend on whether you can identify the function of one of the components of a passage, too. The most obvious kind of these questions are the "two highlighted portions of a passage" questions - onscreen, you'll see two portions literally highlighted in black. You'll be asked to identify the role of the highlighted portions. Note: it's possible these "two highlighted portions" questions have been phased out, but the skill these questions get at will still be tested.
Let's take a look at an example of a normal function question from the Verbal Reasoning Practice Book. (I've added the sentence numbering.)
1.) Supernovas in the Milky Way are the likeliest source for most of the cosmic rays reaching Earth. 2.) However, calculations show that supernovas cannot produce ultra-high-energy cosmic rays (UHECRs), which have energies exceeding 10^18 electron volts. 3.) It would seem sensible to seek the source of these in the universe’s most conspicuous energy factories: quasars and gamma-ray bursts billions of light-years away from Earth. 4.) But UHECRs tend to collide with photons of the cosmic microwave background—pervasive radiation that is a relic of the early universe. 5.) The odds favor a collision every 20 million light-years, each collision costing 20 percent of the cosmic ray’s energy. 6.) Consequently, no cosmic ray traveling much beyond 100 million light-years can retain the energy observed in UHECRs.
Before I get to the question, I want to give you a drill that's going to help with questions like this: classify EVERY sentence in the passage. For the sake of this exercise, I'll simplify the way I classify the sentences:
I purposefully stripped the detail from my classifications since the GRE will often do the same. In real life, you may not need to classify EVERY sentence of a passage - perhaps just the ones in the area you need to work with.
Hopefully my classifications make sense to you. Now, let's check out the question I want to talk about:
In the context of the author’s argument, the last sentence performs which of the following functions?
It's immediately apparent that this is a function question because it asks about function. You might see other wording like "role" or "purpose".
Since we've already thought about what each sentence does, this question becomes a lot easier. I'll go through a common wrong answer choice first, and then talk about the right answer.
Choice E is popular (at least among my students) but wrong. Why? If you look back at the passage, there isn't a main conclusion. The author brings up a theory, shoots it down, then brings up another theory and shoots that one down, too.
Choice C is right, since the last sentence is a conclusion that pertains only to the author shooting down the second theory. The last sentence has nothing to do with the first two sentences of the passage, so it's unfair to say it's the main conclusion. A main conclusion would be something the whole passage leads up to or is about.
One final thing about function that I like to tell my students is that, to understand a sentence, think about it in the context of the sentence before it. How would you describe their relationship? Answering this question will get you thinking about the sentences' functions and help you better understand what's going on.
Here's a video explaining a real GRE function question. Enjoy!