hi i married a usc and am going for my interveiw , does anyone know what sort of things they ask you at the interveiw? do they ask you really personal things?

Yeah they can ask questions like in which positions do you have sex and what color panties does your wife normally wears.

If you have proper proofs and are actually living together, then they do not go in details. Sometime they just ask simple questions about family members of other spouse etc. In case, they have suspicion on your marriage, they they be grill you for sure and will ask all sort of questions.
Good luck.

I was asked when was the last time my wife and I had sex!

Thats most personal it got!

My husband was asked questions like "how many brothers and sisters does your wife have? What are their names?" She also asked us separately some questions like "what did you do last weekend..." to make sure we really were living together and acting as husband and wife.

Normally they try to keep it clean. But, when the validity of the marraige is in doubt they will ask questions as you have read above.

To avoid this, I always recommend that you create a photo album that tells the story of your relationship. Take it with you and provide them with a photocopy of it. I should show your early days before marraige, the marraige and the days after marraige.