Systemic functional linguistics is concerned with understanding the ways in which language is used for different contexts and situations. The emphasis on language as a system explains the name of Hallidays revised theory (systemics). Halliday (1967: 3) clarifies that the name systemic is not the same as systematic; the term is used because the fundamental concept in the grammar is that of the system. A system is a set of options with an entry condition, that is to say, a set of things of which one must be chosen.