Final answer:
The idiom 'A sleeping fox catches no poultry' means that one cannot succeed without actively trying. This is demonstrated in the example sentence where John decides to study more actively.
Step-by-step explanation:
The idiom 'A sleeping fox catches no poultry' is an old proverb that essentially means 'you can't succeed if you aren't actively trying'. It illustrates the need for being proactive and taking initiative. Consider this sentence as an example: John realized that 'a sleeping fox catches no poultry' and decided to start studying more, rather than waiting for the knowledge to come to him. This highlights the fact that John understood he needed to be more active in order to be successful in his studies.
Learn more about English Idioms