【正确答案】正确答案：Halliday's Systemic Grammar is different from other linguistic theories in the following aspects. First, it attaches great importance to the sociological aspects of language. Secondly, it views language as a form of doing rather than a form of knowing. It distinguishes linguistic behavior potential from actual linguistic behavior. Thirdly, it gives a relatively high priority to description of the characteristics of particular languages and particular varieties of languages. Fourthly, it explains a number of aspects of language in terms of clines (i. e. ungrammatical → more unusual → less unusual→ less usual→ grammatical). Fifthly, it seeks verification of its hypotheses by means of observation from texts and by means of statistical techniques. Lastly, it has as its central category the category of the system.