In the following question, a sentence is divided into four parts. Identify the part that contains an error in standard English usage, or select 4 for No error: I was shocked to hear / that her husband / died of an accident. / No error.

Introduction / Context:
Error spotting questions in English grammar are designed to check a learner's awareness of standard idiomatic usage. This sentence talks about someone's reaction to the news of a death, and the error lies in the preposition used with the word died. Examinations frequently test preposition collocations because they are often memorised rather than derived by rule. Understanding which preposition naturally follows a particular verb is essential for correct, natural sounding English.

Given Data / Assumptions:
- The full sentence is: I was shocked to hear that her husband died of an accident.
- It is divided into four parts labelled 1, 2, 3 and 4.
- Part 1: I was shocked to hear
- Part 2: that her husband
- Part 3: died of an accident.
- Part 4: No error
- We must choose the part which contains the grammatical or idiomatic error.

Concept / Approach:
The key concept here is verb plus preposition collocation. In English, we usually say die of a disease or die from an illness but die in an accident. The choice of preposition reflects the typical pattern of usage. The words of and from are used more with internal causes like disease or wounds, while in is used with external events like accidents, fires or wars. Once we recall this rule, we can quickly see that died of an accident is not the natural collocation and needs correction.

Step-by-Step Solution:
Step 1: Examine each part of the sentence: Part 1, I was shocked to hear, is a standard phrase and correct.Step 2: Part 2, that her husband, simply introduces the clause and does not contain any error.Step 3: Part 3, died of an accident, stands out because the preposition of sounds unnatural with accident.Step 4: Apply the rule that we normally say died in an accident, not died of an accident.Step 5: Therefore the error lies in part 3, and the corrected sentence should read died in an accident.

Verification / Alternative check:
To verify, we can compare similar phrases. We say He died of cancer or She died of a heart attack, where of is correct because it states the cause in terms of a disease. In contrast, we say Many people died in the accident or Several passengers died in the crash. Native usage and standard grammar references support die in an accident rather than die of an accident. Since no other parts of the sentence show grammatical problems, part 3 is confirmed as the only incorrect segment.

Why Other Options Are Wrong:
- Part 1, I was shocked to hear, is grammatically correct and expresses a natural emotional reaction.
- Part 2, that her husband, correctly introduces the object clause and does not need any change.
- Part 4, No error, cannot be chosen because we have clearly identified an error in part 3.

Common Pitfalls:
Learners often confuse the prepositions of, from and in with the verb die. They may also be misled by hearing non standard usage in casual speech. Another pitfall is to search for overly complex errors in tense or structure and miss a simpler collocation issue. To avoid this, it is helpful to practise lists of common verb plus preposition combinations and to read widely in order to internalise natural patterns. Remember that in accident or in a car crash is the standard usage in formal English.

Final Answer:
The error is in part 3, because the correct phrase is died in an accident, not died of an accident.