Compound and adverbial complex sentences revision

A comma is a punctuation mark with more than one purpose. Commas are often used to demarcate clauses in a range of sentence types. If the adverbial clause starts an adverbial complex sentence, it is followed by a comma then the main clause. A comma is used before "but" and "or" co-ordinating conjunctions when they join two main clauses in a compound sentence. Grammatically accurate sentences start with capital letters and most often end with full stops.