Can you give me 3 examples of when the subjunctive must be used in Spanish

The subjunctive is used for a change of subject in a sentence eg. Quiero que tu no tengas frío The subjunctive is used with the conjunction 'para que'eg. Debes llevar una chaqueta para que no tengas fríoThe subjunctive is used to express an unknown or uncertainty eg. Cuando + a future act - Cuando tu vayas a la universidad