Improve the bracketed part of the sentence: "We were still waiting in the queue for tickets when the show (had begun)."

Introduction / Context:
This question tests your understanding of correct tense sequencing when describing two past actions, one in progress and one that interrupts it. The sentence is about people still waiting in a queue when the show starts. The bracketed part had begun needs to be checked and possibly replaced with a more appropriate tense to match the rest of the sentence and standard narrative style.

Given Data / Assumptions:

• The full sentence is: We were still waiting in the queue for tickets when the show (had begun).
• The first clause uses past continuous: were still waiting.
• The second clause currently uses past perfect: had begun.
• The options given are was beginning, begins, began, and no improvement.

Concept / Approach:
In English narrative, we typically use past continuous for an action that was in progress and simple past for a second, shorter event that interrupts or occurs during that ongoing action. For example, We were eating dinner when the phone rang. The past perfect (had begun) is used mainly to show that one past action was completed before another past action, often with some gap in time or with explicit reference to earlier time. Here, the show starting and the waiting in the queue are simultaneous in the sense that the show begins while they are still waiting, not long before. Thus, the simple past began after when is the natural tense choice, giving when the show began.

Step-by-Step Solution:
Step 1: Identify the two actions: Action 1, We were still waiting in the queue; Action 2, the show began.Step 2: Recognise that Action 1 is the longer background action, correctly expressed by past continuous were waiting.Step 3: Choose simple past for the shorter action that occurs at a point in time during the longer action, giving the show began.Step 4: Reject had begun because it suggests that the show was already started before the time they were waiting, which confuses the intended meaning.Step 5: Check that We were still waiting in the queue for tickets when the show began sounds natural and matches the standard pattern.

Verification / Alternative check:
Test each option in the context of the entire sentence. Was beginning would create We were still waiting ... when the show was beginning, which is not wrong but is stylistically weaker and less common than began, and it does not express a clear point of interruption. Begins would shift to present tense, We were still waiting ... when the show begins, which mixes past and present inappropriately. No improvement would keep had begun, which implies that the show had already begun before the period of waiting, contradicting still waiting in the queue. Therefore, began is the only fully appropriate option.

Why Other Options Are Wrong:
Was beginning attempts to use continuous tense for both actions, but the clause after when usually prefers simple past to mark a specific event. Begins breaks tense consistency by introducing present tense into a clearly past narrative. No improvement cannot be correct because the past perfect had begun is not justified by any earlier reference point and makes the sentence less clear than necessary. Simple past began fits the classic pattern of background continuous plus interrupting simple past.

Common Pitfalls:
Many learners overuse past perfect whenever they see two past actions, assuming that the earlier one must always be in had + past participle. However, past perfect is only needed when there is a genuine earlier action that must be distinguished from a later reference point. When two actions occur in close sequence, and one clearly happens during an ongoing action, the combination of past continuous and simple past is usually sufficient. Remembering examples like We were watching TV when the lights went out will help reinforce this rule.

Final Answer:
The correct improvement is to replace had begun with began, so option C is correct.