akhil911
Due to the slow-moving nature of tectonic plate movement, the oldest ocean crust is thought to date from the Jurassic period,
formed from huge fragments of the Earth's lithosphere and lasted 200 million years.A. formed from huge fragments of the Earth's lithosphere and lasted 200 million years.
B. forming from huge fragments of the Earth’s lithosphere and lasting 200 million years.
C. forming from huge fragments of the Earth’s lithosphere and lasted 200 million years.
D. formed from huge fragments of the Earth’s lithosphere and lasting 200 million years.
E. formed from huge fragments of the Earth’s lithosphere and has been lasting 200 million years.
OFFICIAL SOLUTION
The correct response is (D).
The meaning of the sentence is that the “oldest ocean crust” was “formed” in the past during the Jurassic period and is currently still “lasting” (since if it’s the “oldest” it must still be around!). We need the past tense/participle verbs to be used correctly.
If you chose (A), the ocean crust was “formed” in the past” but if “lasted” is past tense then the oldest ocean crust is no longer around, which would mean it couldn’t be the “oldest.”
If you chose (B) or (C), “forming” implies the crust is still being formed. While it’s true the Earth’s crust is constantly in flux, we’re concerned with the “oldest ocean crust” – that part that is no longer continuing to form, but was formed at some point during the Jurassic period.
If you chose (E), you correctly used “formed,” however the present perfect “has been lasting” is unnecessarily wordy. The simple participle verb form will suffice.
Does logic dictate that (D) is the correct answer? Yes. Will you ignore it because it uses past participle form modifying the previous subject/clause instead of ‘Jurassic Period’? No. Note that it is correct grammatically and you should know it. Whatever we can infer about the preferences of GMAT is from the questions it gives. GMAT doesn’t clarify its stand on every grammatical issue and the stand is probably flexible depending on the sentence under examination. So you need to be flexible in your understanding of what is and is not acceptable in GMAT. Use logic – remember, GMAT is a test of your reasoning skills. Get to the best answer under given circumstances.