In the following sentence, a part of the sentence may contain an error. Identify the part that has an error and select the correct option. If the sentence is free from error, select 'No Error'. The lady was knocked down (1) / by a speeding car (2) / upon crossing the road. (3) / No Error (4)

Introduction / Context:
This is a standard English grammar error spotting question. Learners must identify which part of the sentence contains a grammatical or usage error. The sentence describes an accident involving a lady and a speeding car. The key focus is on the correct use of prepositions and phrases to show when the accident occurred in relation to her action of crossing the road.

Given Data / Assumptions:

• The sentence is divided into four parts, labelled (1), (2), (3), and (4).
• Part (1): "The lady was knocked down"
• Part (2): "by a speeding car"
• Part (3): "upon crossing the road."
• Part (4): "No Error"
• The structure aims to express that the lady was hit while she was crossing the road.

Concept / Approach:
The main concept here is correct idiomatic usage in English. Native and standard usage prefers "while crossing the road" rather than "upon crossing the road" in this context. The preposition "upon" usually suggests immediacy after completion of an action, not the action in progress. To describe an accident that happened during the act of crossing, the progressive idea "while crossing the road" is more precise and natural. Therefore, the error lies in the phrase used in part (3).

Step-by-Step Solution:
Step 1: Examine part (1) "The lady was knocked down". This is grammatically correct and clearly states the action. Step 2: Examine part (2) "by a speeding car". This correctly uses the preposition "by" with a passive verb to indicate the agent of the action. Step 3: Examine part (3) "upon crossing the road." The phrase sounds awkward for describing an accident happening during the act of crossing. Step 4: Replace the phrase mentally with "while crossing the road", which clearly expresses that the accident took place during the crossing. Step 5: Conclude that part (3) contains the error and therefore select option 3 as the answer.

Verification / Alternative check:
A quick test is to read the sentence aloud after correcting part (3): "The lady was knocked down by a speeding car while crossing the road." This sounds natural and is standard English usage. In contrast, "upon crossing the road" usually implies that she finished crossing and then something happened immediately afterward, which is not the intended meaning. Parts (1) and (2) are structurally correct and do not require any changes. Thus, only part (3) is faulty.

Why Other Options Are Wrong:

• Part 1: "The lady was knocked down" is a correct passive voice construction with no grammatical error.
• Part 2: "by a speeding car" properly introduces the agent of the action in passive voice.
• Part 3: "upon crossing the road." is incorrect in this context and should be replaced with "while crossing the road".
• Part 4: "No Error" cannot be selected because we have clearly identified an error in part (3).

Common Pitfalls:
A common mistake is to overlook subtle differences between similar prepositions such as "upon" and "while" or to assume that any formal sounding phrase must be correct. Students may also be distracted by the passive voice and look for errors in parts (1) or (2), even though those parts are standard. Paying attention to idiomatic usage and the exact intended time relation between actions is crucial in such questions.

Final Answer:
The error lies in part (3), so the correct choice is 3.