Codes and conventions of radio trailers

Voice-over- Sometimes starts with a question this gets the audience to think about the question, it's used to say what the documentary is about. The voice-over is used to speak only a couple of sentences.

Background music- the background music rises and falls in volume depending on the other sound in the radio trailer.  It makes the trailer more interesting and fits the documentary.

Sound bites- these can be sound clips for interviews from the documentary these are relevant to the documentary, highlights(taster) of the documentary  There is also something funny/serious to fit the documentary.