15 A. Condition — the grammar of every rule's boundary

1. Zero & first conditional (real): "If a cheque is dishonoured, the payee may prosecute." (statutory style: present + modal)2. Second conditional (hypothetical): "If the agreement were oral, proof would be difficult."3. Third conditional (past unreal): "If the notice had been served, the suit would have been within time."4. Unless = if… not: "The appeal shall be dismissed unless the defect is cured within fifteen days."5. Provided that / save that / except if — statutory conditions and exceptions.6. In the event of/in the event that: "In the event of insolvency, the security shall crystallise."Drafting tip: keep conditions at the front of the sentence, complete, and in the same tense family as the consequence; never nest a condition inside a condition.