The question asks students to complete a first conditional sentence using an imperative. The context explains that when using first conditionals for real or possible future situations, the main clause can use an imperative (command or advice) instead of 'will + verb'. Given the passage's theme about following one's passion and conviction—'if it is still burning in your blood and you are ready to commit yourself to the task, plunge' and 'go ahead and do something about it'—an appropriate imperative like 'pursue it' fits naturally. Other valid imperatives could include 'go ahead', 'plunge', or 'do something about it'.