56. What is the primary purpose of this passage?
(A) To explain an approach to language study
(B) To introduce a theory of language learning
(C) To give an example of language elements
(D) To illustrate a method of analyzing spoken utterances

先透過topic sentences (大約是文章前三句) 判斷整篇主旨

In the 1950s, structural linguistics had developed in part as a reaction to traditional grammar.

The scientific approach to the study of language was thought to consist of collecting examples of what speakers said and analyzing them according to different levels of structural organization rather than according to categories of Latin grammar.

接著來看選項(我用我的思考邏輯說明):

(A) To explain an approach to language study (正解) (B) To introduce a theory of language learning

1. 並未提到確切理論，而且根據我閱測以來的經驗，通常有提到理論會順帶的把學者名字提出，還會提到實驗的過程(何以有此理論)或是實例(此理論適用的狀況)

(C) To give an example of language elements

1. 文章裡沒有具體例證，也沒有for instance相關的副詞，更多的是條列式的說明；文中第一段第二句提到的examples只是個名詞，並未有詳細敘述；再者，elements只是把元素名稱(morpheme, phonemic systems...etc)列舉出，並無相關的說明

(D) To ilustrate a method of analyzing spoken utterances

1. 由快速瀏覽第一段末尾條列出structural characteristics、第二段開頭Learning a language可知闡明方法的篇幅並不多，所以不會選項