(one of the main features), TV documentaries use interviews to make a contrast between observation sequences. They can either be completely uninterrupted or they can be in fragments of observation.
Putting the audience in a role of an eye witness. The programme makers pretend the camera is unseen.
Sequences are dramatised to portray people and events the film maker cannot gain access to in real life (reconstruction).
The directors and producers carefully construct a set with a particular location that supports the idea of the documentary as well as what props will be used in shots as well as their attire (for an interview).
The argument of the documentary, what the documentary is saying. Sequences can be used to allow the audience to make their own conclusions.