Союзы - Соединения причины и следствия

used for introducing the reason of something

потому что

used to express a reason for something happening, existing, etc.

с тех пор

used to summarize or draw a conclusion based on previous information or to provide a logical inference

так что

used to provide a reason, explanation, or context for the main clause

used to indicate a result or outcome related to what has just been said or happened

теперь

used to provide context or justification for an action, decision, or statement