Pony.ai Software Engineer interview questions

I have got a phone interview that was scheduled one month later. It is hard to communicate with the interviewer in English. I should have just used Chinese from the beginning. Though I am not a native speaker but the interviewer's English level is very low. You should directly speak Chinese if you were Chinese or speak very very slow. I mentioned about adjacency list when doing the graph topological sort for many times but the interview seemed not know what it is.