exporting audio problem

Hi, I edited a video but everytime I try to export it with the audio, it's silent. I also tried to export only the audio, and it doesn't work. I don't what I should do or what is the problem, the audio works in the deliver page and in all the pages. I read something about synchronizing audio and video, but I don't think it's my problem. What I did with audio was just modifying pieces, unlinking it from the original videos and linking it with others.
I'm new to Davinci Resolve, so it may be a very basic thing.