Will I look stupid if I'm not sure about a particular audit procedure?

They don't expect you to not know everything and assume you'll ask a lot of questions. One thing they encourage you to do is accumulate a list of questions and set aside some time with your manager to address everything on the list rather than stopping them every five minutes for another question. Of course if you run into a situation where you can't do anymore work without getting an answer,  you want to ask your supervisor right then and there.

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