父(ちち) chichiが ga病(びょう)気(き) byoukiだった dattaので node、私(わたし) watashiは wa家(いえ) ieに niい iなければならなかった nakerebanaranakatta。 Since my father was sick, I had to stay home. Literal Father [subject-が] sick was [because-ので], I [topic-は] home [at-に] be-must was. A clean cause-and-effect sentence with ので. ~なければならなかった is the past obligation form. familyhealth~ので (because)~なければならない (must)
父(ちち) chichiが ga病(びょう)気(き) byoukiだった dattaので node、私(わたし) watashiは wa家(いえ) ieに niい iなければならなかった nakerebanaranakatta。 Since my father was sick, I had to stay home. Literal Father [subject-が] sick was [because-ので], I [topic-は] home [at-に] be-must was. A clean cause-and-effect sentence with ので. ~なければならなかった is the past obligation form. familyhealth~ので (because)~なければならない (must)