Physicist Stephen Hawking made remarkable contributions to theoretical physics, notably in black hole theory. Hawking’s work holds immense significance for cosmologists, who require complex mathematical equations to understand the universe’s intricacies.Choice A is the best answer. The convention being tested in fragmentation, which refers to a group of words that is not a complete sentence but is punctuated as one. Relative clauses, such as the one beginning with “who,” require a verb that can function as the main verb of a clause. This choice correctly supplies the clause with the present tense verb “require.”
Choice B: The to-infinitive “to require” cannot function as the main verb of the sentence.
Choice C: The past tense verb “required” does not agree in tense with the previous verb of the sentence “holds.”
Choice D: “Having required” is a participle and cannot function as the main verb of the sentence.
✨ Expert's Tip ✨
To check whether your answer choice is correct, create a sentence using the antecedent (the word preceding the relative pronoun) as the subject and the verb from the relative clause as the main verb.
