If I were a bird, I _____ fly.

If+past indefinite, subject + would/ could/might +V1.

If I were a bird, I would fly. This sentence is a second conditional (subjunctive mood) structure used to describe a purely hypothetical, imaginary, or contrary-to-fact situation in the present, where "were" is used for all subjects and "would" + base verb is used in the main clause.

Grammatically Correct Answer: "If I were a bird, I would fly".

Reasoning: Because the premise "If I were a bird" is an impossible, imagined scenario, it requires the past subjunctive form "were" (instead of "was") and the conditional "would" to show the result.

Alternative Structure: "If I were a bird, I could fly." (Using "could" emphasizes the ability rather than just the action).

Second conditional sentence -  এর  পরবর্তী অংশ বাক্য গঠনের নিয়ম Subject   +   would/could/might   +   verb এর present form   +   extension.