English grammar — sentence improvement (verb form after auxiliary 'did'): Choose the correction that makes the sentence grammatically correct and natural in standard written English. Original sentence: "Why did you not threw the bag away?" Select the best replacement for the underlined segment (verb phrase) to complete the sentence correctly.

Given data

• Sentence uses auxiliary did in an interrogative: "Why did you not ___ the bag away?"
• Options vary the form and order of the main verb throw.

Concept/Approach
In questions with the auxiliary do/does/did, the main verb appears in its base form (bare infinitive). Past simple is carried by did, not by the main verb.

Step-by-step check
A. "did you not throw" → base form after did ✔B. "had you not threw" → wrong auxiliary and wrong past form ✖C. "did you not thrown" → past participle after did ✖D. "you did not thrown" → wrong order for a question and wrong form ✖E. "No correction required" → incorrect because "threw" cannot follow "did". ✖

Correct construction
"Why did you not throw the bag away?"

Common pitfalls
Using past/participle (threw/thrown) after did; forgetting inversion in questions.

Final Answer
did you not throw