In this sentence improvement question on reported speech, choose the best alternative to express the idea correctly: Will you tell me who did accompany you to the airport?

Introduction / Context:
This grammar question tests your understanding of correct word order and auxiliary verb usage in an indirect question within a larger sentence. The original sentence is slightly awkward and ungrammatical because of the unnecessary auxiliary "did" before "accompany". To improve the sentence, you must know how to form indirect questions in English when they follow a main clause such as "Will you tell me".

Given Data / Assumptions:
- The given sentence is: Will you tell me who did accompany you to the airport?- The part to be improved is the clause "who did accompany you".- The options are: "when did accompany you", "who must be accompanied you", "who accompanied you", and "No improvement".- The intended meaning is to ask for the identity of the person who went with the listener to the airport.

Concept / Approach:
In English, indirect questions introduced by phrases like "Will you tell me", "Do you know", or "Can you say" generally use normal statement word order and do not require an extra auxiliary "do" when the main verb is already in the past tense. "Who accompanied you" is a simple past statement. When you embed it in a larger sentence as an object clause, you keep the same structure. The auxiliary "did" is only used in direct questions or to add emphasis. Here, it makes the clause sound unnatural and incorrect.

Step-by-Step Solution:
Step 1: Identify the main clause: "Will you tell me". This introduces an indirect question.Step 2: Identify the embedded clause: "who did accompany you to the airport".Step 3: Recall that in indirect questions, the clause after "who", "what", "when", etc. usually follows statement order, for example, "who accompanied you", not "who did accompany you" unless strong emphasis is intended.Step 4: Remove the unnecessary "did" and check the remaining clause: "who accompanied you to the airport". It is clear and grammatically correct.Step 5: Compare with the given options and select "who accompanied you" as the best improvement.

Verification / Alternative check:
You can verify by constructing similar sentences: "Will you tell me who helped you", "Can you tell me where you went", "Do you know who called you". In these examples, there is no auxiliary "did" after the wh word, because the verbs "helped", "went", and "called" are already in the simple past. If you insert "did" unnecessarily, the sentences sound wrong or overly emphatic. This pattern confirms that "who accompanied you" is the correct form here.

Why Other Options Are Wrong:
Option "when did accompany you": Incorrect because it uses "when" instead of "who" and omits the subject "you", producing a grammatically incomplete clause.Option "who must be accompanied you": Wrong because "must be accompanied" would require passive structure such as "must be accompanied by", which does not fit the intended meaning of asking who went with you.Option "No improvement": Incorrect because the original clause with "who did accompany you" is unnecessarily emphatic and unidiomatic in this context.

Common Pitfalls:
Learners sometimes think that every past tense question must use "did", even in indirect questions. They may also overuse auxiliaries because they are common in direct interrogative sentences. Another pitfall is failing to distinguish between direct questions ("Who did accompany you?") and indirect questions embedded in statements ("Tell me who accompanied you"). To avoid these mistakes, remember that indirect questions usually follow the normal statement order and do not need an extra auxiliary when the main verb is in simple past or present.

Final Answer:
The best improvement is who accompanied you, so the correct sentence is: Will you tell me who accompanied you to the airport?