how does explicit and implicit instruction of formal meta discourse markers affect learners’ writing skills?

Discourse markers improve both the quality and comprehension of a written text. this study aimed at investigating the effect of explicit and implicit instruction of formal metadiscourse markers on writ ing skills. the quantitative data were collected from 90 upper intermediate students at shiraz university language center. two experimental groups went through an instruction, while the control group did not receive any instruction on formal metadiscourse markers. a pre-test post-test method of as sessment was employed. after an eight session treatment, a posttest was administered to compare the participants‟ performances. the results revealed that the instruction of formal metadiscourse markers had a positive effect on the learners‟ writing skills. moreover, the results showed that learners who received explicit instruction of metadiscourse markers could perform better in writing than learners who received implicit instruction. the findings can have pedagogical implications for efl educators and materials developers to enhance learners‟ writing skill. furthermore, the findings provide impor tant insight into the impact of teaching discourse markers and raising learners‟ awareness through ex plicit instruction in order to make pupils produce more cohesive and coherent written texts. besides, it sheds light on the effect of different types of instruction on learning metadiscourse markers and its application in writing skills.