This research aims to investigate the effects of two teaching sequences -- interleaving and blocking -- on the participants' use of three types of cohesive devices (conjunctions, conjunctive adverbs and prepositions [thereafter CCPs]) in their argumentative essays. The participants included 50 native Cantonese-speaking university students taking an academic writing course. Interleaving refers to the teaching sequence in which learners practice several skills at one time whereas in blocking only one skill is practiced at one time. Prior to essay writing, participants were taught CCPs using sentence transformation. One class was taught using interleaving and the other blocking. The first and the second drafts of the argumentative essay served as pre-and post-tests. The total numbers of CCPs used correctly both syntactically and semantically in their argumentative essays were counted for the pre-tests and post-tests for both groups. Results of Paired Samples and Independent t-tests suggest that neither of the two teaching sequences was more effective than the other in raising the participants' total instances of CCPs; however, blocking appears to be more effective in boosting the use of prepositions as linking words. Sentence transformation, whether administered in the interleaved or blocked sequence, was considered to have served the teaching purpose of providing an opportunity for the students to engage in serious thinking about the semantic relationship between two given sentences. [This paper was published in "Education, Language and Sociology Research" v4 n3 p31-49 Jul 2023.]