MGMAT CAT EXAM - Sentence Correction - Molten Rock

[zhangchenyuan]

Geologists once thought that the molten rock known as lava was an underground remnant of Earth's earliest days, sporadically erupting through volcanoes, but they now know that it is continuously created by the heat of the radioactivity deep inside the planet.

A. was an underground remnant of Earth's earliest days, sporadically erupting

B. had been an underground remnant of Earth's earliest days and sporadically erupted

C. was an underground remnant of Earth's earliest days, which sporadically erupted

D. would be an underground remnant of Earth's earliest days that sporadically erupted

E. was an underground remnant of Earth's earliest days, having sporadically erupted


OA is A

the explanations are:
The original sentence does not contain any errors. The verb clause "was an underground remnant of Earth's earliest days" is correct in tense (simple past "was") and number (singular "molten rock" paired with singular "was"). Moreover, the modifier "sporadically erupting through volcanoes" correctly modifies the preceding clause.

(A) CORRECT. This choice is correct as it repeats the original sentence.

(B) This choice unnecessarily and incorrectly changes the simple past "was" to the past perfect "had been," which is used only when describing the earlier of two past actions. Moreover, the use of "and" here equates the geologists' false understanding of lava with the fact that it sometimes erupts through volcanoes.

(C) This choice improperly uses the relative pronoun "which" to modify "Earth's earliest days" instead of "molten rock known as lava."

(D) This choice incorrectly changes the simple past "was" to the conditional "would be." Moreover, the use of "that" implies that eruption through volcanoes was part of what the geologists erroneously believed about lava.

(E) In this choice, "having sporadically erupted" incorrectly places this modifier in the past tense, implying that lava no longer erupts through volcanoes.

My choice is C. and i still don't get why A is right. Manhattan SC Guide stated that "the -Ing form is very flexible. 1. It can modify nouns directly (e.g., the changing seasons). 2. It can modify verbs and their subjects (e.g., llifted the weight, whistling). 3. It can even modify an entire clause as above, as long as the entire clause converted into a noun phrase could function as the subject of the verb that is now in -Ing form. " which role does the -ing form in choice A play? and as for the explanation for choice C, i don't get it neither. isn't choice C is an example of the exceptions to the touch rule--a "mission-critical" modifier falls between. This modifier is often an Of phrase that defines the noun. The less important modifier refers to the noun plus the first modifier?

can anyone explain this to me? thanks so much!

[zhangchenyuan]

I'm going to take the test tomorrow, can anybody help me with the question? thanks so much in advance!

[tim]

This is not an on-demand question answering service. Remember that we have office hours and private tutoring for the truly urgent questions; there are a lot of students using this free service, and when you post here, you have to accept the fact that it could take a while to get your answer..

As for your question, you quote relevant passages from our SC guide that describe just how versatile an -ing word is but yet you somehow use this as a reason to reject A rather than embrace it. Here’s the thing: if you don’t get why A is right, that means you must have found a grammar error in it. What is the grammar error? As for C, "which" is more strongly attached to the closest eligible noun preceding it and is therefore not subject to the mission critical modifier exception for the most part..