答案:1.Definition
Discourse markers are the expressions that are commonlyused in the initial position of an utterance and are syntacticallydetachable from a sentence. 2.Functional-pragmatic nature(1) In narratives
In narratives , it is very common to find discourse markersas part of the temporal strategy of discourse , that is , of thepresentation of new events as occurringlater in time than thosealready narrated
(2) In non-narratives
In non-narrative texts, discourse markers have the func-tion of bracketing discourse. 3.Features of discoursemarkers( 1) They do not belong to the sentence elements proper ( sub-ject , verb , complement) ;(2) They are typically found in utterance initial position or ,on the whole , in transitional locations ( beginning and end ofunits);
(3) They do not always have a clear propositional ( semantic)meaning or their propositional meaning is superseded by theirdiscoursal functions ;(4) They assume multiple roles in signaling relations ( ide-ational, textual and interpersonal) between units at differentlevels.