Complete the sentence: ‘He succeeded _____ hard work.’

The correct preposition to complete the sentence 'He succeeded _____ hard work' is 'through'. This choice accurately conveys the idea that hard work was the means or method by which success was achieved. The preposition 'through' in this context means 'by means of' or 'as a result of,' indicating the channel or instrument that led to the outcome. For instance, one might say, 'She learned English through immersion' or 'They achieved their goals through perseverance.' While other prepositions like 'by' or 'with' can sometimes indicate means, 'through' specifically emphasizes the process or the journey undertaken to reach a particular state or accomplishment. 'By' might imply agency ('He succeeded by himself'), and 'with' might suggest accompaniment or possession ('He succeeded with great effort,' which is close but less direct than 'through'). 'From' would imply origin, which is incorrect here. Therefore, 'through hard work' clearly articulates that hard work was the instrumental factor in his success, making it the most fitting and grammatically sound option.