“Modification” on the GMAT refers to words, phrases, or clauses that function as descriptors. Some modifiers include adjectives, adverbs, prepositional phrases, etc. Try this Sentence Correction question on your own, then review the correct answer below!

No matter how patiently they explain their reasons for confiscating certain items, travelers often treat customs inspectors like wanton poachers rather than government employees.

(A) travelers often treat customs inspectors like wanton poachers rather than government employees
(B) travelers often treat customs inspectors as wanton poachers instead of government employees
(C) travelers often treat customs inspectors as if they were not government employees but wanton poachers
(D) customs inspectors are often treated by travelers as if they were wanton poachers rather than government employees
(E) customs inspectors are often treated not like government employees but wanton poachers by travelers

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The main error here is one of modification. An opening clause describing an action with a comma at the end of it must be immediately followed by the person or thing DOING the action.

“No matter how patiently they explain their reasons for confiscating certain items,” is the opening clause here. We can ask, who is logically doing the “confiscating”? It wouldn’t be the travelers, since it’s illogical that they would confiscate their own belongings.

Based on this logic alone, we can eliminate A, B, and C.

For E, there are several issues. “By travelers” is far from its verb “treated” and has faulty parallelism. Since the first part of the idiom begins with “like”, we would want “like” to follow the word “but” as well.

That is why the correct answer is (D).