Step 1: Understand the relationship between the two clauses. Clause 1: Siti practised every day (suggests she should be prepared). Clause 2: She forgot her opening bars on stage (unexpected, opposite outcome). Step 2: Identify the relationship. The two clauses contrast each other — despite preparation, something went wrong. Step 3: Match the relationship to a conjunction. 'However' signals contrast or an unexpected turn. Answer: 'however'.