An analogy matches the relation between ordered terms. Topic similarity is insufficient: a pair of objects from the same passage may relate differently. Establish what the first term does in relation to the second, then carry that sentence into each candidate pair without reversing its direction.
Reason through the task
Use a short linking sentence: a symptom signals a cause; a tool enables an action; one part contributes to a whole. Check the passage before deciding the relation, because an object’s local role may matter more than its usual meaning. For A:B::C:D, test both whether A relates to B as C relates to D and whether the degree of dependence matches. Enabling is weaker than guaranteeing; describing is different from creating.
Worked example and a tempting error
Original scene: a loose bolt makes a bicycle wheel rattle. A rider uses a diagram to locate the bolt. Rattle : loose bolt matches smoke : fire when smoke signals the fire producing it. Fire : smoke reverses cause and sign. Diagram : bolt is representation to object rather than symptom to cause. Wrench : bolt is tool to the object acted upon. All four pairs involve plausible connections, but only one preserves the selected causal-sign relationship.
Try a different case
Transfer: a painted backdrop contributes to a play’s effect alongside actors, words and audience attention. Backdrop : performance matches violin : orchestra for a contributing part within a larger combined activity. Conductor : orchestra introduces direction or leadership instead of component membership. Orchestra : violin reverses whole and part. Explain the relation aloud before looking for shared vocabulary; that explanation is your check against an attractive but differently ordered pair.