2。2。1 Ideational Function

    The traditional grammar gives a definition to the passive voice from the perspective of structure。 A sentence that fits the structure of “be+ V+ed” is a passive sentence。 But it may not be comprehensive to judge a sentence if it is passive voice only by its structure。 For example: 

    The house won’t sell。

    This sentence is not a passive voice sentence judging by its structure。 However, it is clear that this sentence implied passive meaning。 Halliday tried to analyze from the perspective of the ideational function。The ideational function contains transitivity, voice and polarity。 The transitivity is an important system in ideational function。 It can pide the sentence into several processes and point out the participant and circumstance in the process。 It is a good way to judge whether a sentence is a passive sentence or not by analyzing the relation between the participants。 

2。2。2 Interpersonal Function

    In English, a sentence can be pided into two parts: mood and resodie。 Mood includes two parts: the subject and the finite。 And the other components in the sentence are collectively called resodie。 Example: