English Grammar | Using a comma with discourse markers To summarize, it's clear that renewable energy sources are vital for future sustainability. [correct] To summarize it's clear that renewable energy sources are vital for future sustainability. [incorrect] Considering for instance, the adoption of electric vehicles. [incorrect] Considering, for instance, the adoption of electric vehicles. [correct] Discourse markers Discourse markers are words or phrases that help connect ideas in a text. They are usually set apart from the rest of the text with commas. Typically , a comma follows a phrase or adverb that introduces a sentence. Furthermore , many individuals experience discrimination in their workplace. Conversely , the rate of unemployment has decreased. In conclusion , it's necessary for local councils to evaluate the expenses associated with recycling programs. Regrettably , all the tickets were sold out. Likewise , animals that live o...