“Separable words” are words that can either be separated or combined in Mandarin Chinese. This is one of the most commonly used forms of expression in the spoken Mandarin. It is also one of the most difficult structures and one that most students try to avoid. According to past research findings and the analysis of the interlanguage corpus, the grammatical order and semantic (or pragmatic) functions of separable words are among the most challenging of learning needs; therefore, this paper focuses on the “separated” type of separable words. By adopting the methods of corpus linguistics, we first extract the intervening structure of the separable words from the Sinica corpus, and then segment the structural component by original part-of-speech. We end up acquiring 10 core components of the intervening structure of separable words, and sort them in the following order: “complement of Verb > aspect marker > DE the nominalized marker > object of Verb > determiner > number > quantifier > adjective/noun phrase modifier/verb phrase modifier” in accordance with syntactic theory and the instances of the Sinica corpus. We also indicate the syntactic restrictions on the interposing elements of separable words, which can then be used as the bases for error-sentence correction. Moreover, through a comparison of the usages of learners and of native speakers, we find that the current textbook examples seem not to meet the practical needs of students and teachers. This observation suggests that the frequency table of separable words and the frequency table of interposed elements analysis should be adopted as a reference for separable-words teaching.