If you were unfamiliar with au fur et à mesure, you had no chance of understanding the sentence. You had to already know that this expression existed. In addition, you probably had to have already heard how it sounds. Only then could you have had a chance at recognizing it in the conversation.
So, there is good news and more good news:
The good news is that, now you know it. 🙂
The other good news is that you can learn other expressions like this on your phone while walking the dog, cleaning the house, riding the subway…
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