IMO D

Hi!

IMO D

There are 3 issues here: appropriate verb tense, parallelism, and pronoun-antecedent agreement.

1) appropriate verb tense
We use the past perfect for an action which finished in the past and whose result was visible in the past.
Therefore, past perfect is appropriate here.
There is 3/2 split. We should eliminate answer choices A, B, and C because of verb tense error.

2) parallelism
example of good parallelism:
"...sudden and unexpected failure..."
example of faulty parallelism:
"...suddenly and unexpected failure..."
We should eliminate answer choice E

3) pronoun-antecedent agreement
"the Large Hadron Collider" is in singular. Therefore, 'its' should be used instead of 'their'.
However, singular 'their' is also used in English.

Read "Top 10 Tips for the Sentence Correction Section" by Chris Black
https://www.beatthegmat.com/mba/2010/09/ ... on-section

Read more about "Pronouns and Pronoun-Antecedent Agreement"
https://grammar.ccc.commnet.edu/grammar/pronouns.htm

Hope it helps!
Best,
Maciek

pradeepkaushal9518 wrote:Reporting that one of their more crippling malfunctions has been the sudden and unexpected failure of the liquid helium cooling system, the engineering squad supervising the Large Hadron Collider requested additional funding to develop better maintenance systems.

A their more crippling malfunctions has been the sudden
B their more crippling malfunctions has been the suddenly
C its more crippling malfunctions is the sudden
D its more crippling malfunctions had been the sudden
E its more crippling malfunctions had been the suddenly

we can eliminate ABC because of using present tense and present perfect tense, we need past tenses
suddenly is not good in E it should be an adjective thus the answe is D