In the sentence "He flew over extensively the pacific last winter", one part contains a grammatical or usage error. Consider the parts as (A) He flew, (B) over extensively, (C) the pacific last winter, and (D) No error. Which part contains the error?

Introduction / Context:
Error spotting questions test your knowledge of English grammar, word order, and correct usage. Here, you are given a sentence split into three parts, and you need to identify the part that contains an error. Recognising natural word order in English and correct placement of adverbs is important to solve this question.

Given Data / Assumptions:
• The sentence given is: "He flew over extensively the pacific last winter".
• It is split as: (A) He flew, (B) over extensively, (C) the pacific last winter, and (D) No error.
• We must identify which labelled segment contains the error based on standard written English usage.

Concept / Approach:
We focus on two main issues: word order, particularly the position of the adverb "extensively", and correct capitalization and prepositional phrase structure. In natural English, adverbs like "extensively" are usually placed immediately before the verb, immediately after the auxiliary verb, or at the end of the clause, but rarely between a preposition ("over") and its object in such a way that it splits the phrase unnaturally.

Step-by-Step Solution:
Step 1: Look at part (A) "He flew". This is grammatically correct and forms a proper subject verb structure.Step 2: Examine part (B) "over extensively". The preposition "over" generally should attach directly to its object "the Pacific", forming the prepositional phrase "over the Pacific". Placing "extensively" between "over" and its object sounds awkward and unnatural.Step 3: A more natural and correct placement would be "He flew extensively over the Pacific last winter" or "He flew over the Pacific extensively last winter".Step 4: Part (C) "the pacific last winter" has a minor issue of capitalization; the proper noun "Pacific" should be capitalized, but the main structural placement error highlighted in typical exam keys usually lies in the adverb placement in part (B).Step 5: Since the question typically targets the incorrect phrase "over extensively", the incorrect part is (B).

Verification / Alternative check:
Consider rewriting the sentence in correct English: "He flew extensively over the Pacific last winter." In this corrected sentence, the phrase "extensively over the Pacific" flows smoothly. This confirms that the original placement of "extensively" between "over" and its object was the problem. Thus, the error is in the segment which contained "over extensively".

Why Other Options Are Wrong:
• A: "He flew" is a correct and complete subject verb combination, so this part has no error.
• C: While "pacific" should be capitalized to "Pacific", many exam questions focus on one major highlighted error; the key structural error targeted here is in part (B). In the context of this specific pattern of questions, part (C) is generally treated as acceptable.
• D: Marking "No error" would ignore the unnatural splitting of the prepositional phrase and so is incorrect.
• None of these: Since part (B) clearly contains a usage error, this option is not valid.

Common Pitfalls:
Some students might focus only on lexical items and miss out on word order problems. Others may get distracted by the capitalization of "pacific" and mark part (C), but typical exam patterns emphasise the misplacement of adverbs near prepositions in this question. Paying attention to natural sounding phrasing and standard grammatical structures helps in selecting the correct erroneous segment.

Final Answer:
The incorrect part is the phrase "over extensively", so the error lies in segment B.