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hence; for that reason
彼は病気だ。其の為会議を欠席した。
He is sick. Therefore, he was absent from the meeting.
電車が遅れた。其の為、約束の時間に遅刻した。
The train was delayed. Therefore, I was late for the appointment.
勉強を頑張った。其の為試験に合格できた。
I studied hard. Therefore, I was able to pass the exam.