I guess you just graduated. Generally speaking, a system is usually completed by many people. If the interviewer asks you, he won't ask you very unfamiliar questions. He will usually ask you to introduce what this system does, what technology it usually uses and what part you do. What is the business process of your part? What technology did you use to complete your part? What difficulties did you encounter in the process of doing it, how did you solve it, and what do you think you gained from this project? This requires you to be really familiar with what you do.