There are a number of elements in language that are inherently ʻgivenʼ in the sense that they are not interpretable except by reference to some previous mention or some feature of the situation: anaphoric elements (those that refer to things mentioned before) [...] Typically these items do not carry information focus; if they do, they are contrastive. So when we say that, of any information unit, the unmarked structure is that with the focus on the final element, this excludes any items that are inherently given.
- Halliday (1985), a pag.277