Originally developed for detecting air pollutants, a technique called proton-induced X-ray emission, which can quickly analyze the chemical elements in almost any substance without destroying it, is finding uses in medicine, archaeology, and criminology.
3 Explanations
▲
1
Billy Yuan
In the first modifier of answer choice (A), isn't the antecedent of "it" unclear? (In the video, the "it" portion of the sentence wasn't written out). Logically, "it" refers to the substance, but couldn't "it" also refer to the technique? Choice (E) refers to "it" as the substance and avoids ambiguity, but it does sound repetitive and awkward. Thanks!
Hi Billy, pronouns usually refer to the closest noun that they agree with (in number and gender). In this sentence, "substance" is right before the pronoun "it," and is much closer than "a technique," so it's clear that the antecedent of "it" is "substance."
Also keep in mind that "it" is not in the first modifier of the sentence - the first modifier is "originally developed for detecting air pollutants"!
Hi Meishan,
In this case, "proton-induced X-ray emission" IS referring to the "technique;" it is the name of the technique, so "which" can be said to refer to either.
"proton-induced X-ray emission" is the full noun , so we wouldn't say that "which" modifies "emission" only.
Note that there are exceptions to the "touch rule," which Mike discusses in the Magoosh lesson "Exceptions to the Touch Rule" as well as in this blog post:
3 Explanations