Do they take away your foreign passport at the interview?

[sizzle33]

Hi! My test is tomorrow. I was wondering if they will make you give up your foreign passport at the spot?

[N400questions]

Certainly not at the interview. Until you are a US citizen you remain a citizen of your original country with all the rights of the original country. You may also want to travel in the meantime.
They only want to see your passport(s) to look for evidence of travel dates and countries visited and visas etc.

[newacct]

The US does not care whether you have foreign citizenship or foreign passports after naturalization, and it is not in a business to adjudicate other countries' nationality laws for whether you still have that country's nationality or not. It just doesn't care. The US won't take away your foreign passport.