There is a circumstance in which we can start a sentence with “because” and not be violating any silly rules. As such, it’s not a stand-alone sentence like the main clause is. The main clause can come first or last; if it comes last, you need a comma. As an example: Because it was hot outside, we decided to go to the pool. Since both of the clauses are in the same sentence, … Writing becomes more interesting when we utilize a combination of dependent and independent clauses in accordance with the rules of grammar. A main clause is something that could be a complete sentence by itself. When you start a sentence with “because,” you have to be sure that you use both clauses to make the sentence a complete one, like this: “Because I’m confused, I’m reading about starting sentences.” It’s a perfectly legal sentence.

If we start a clause with “because”, then insert a comma, and then a second clause, then both of the clauses are in the same sentence and everyone is safe. Students and of course business writers should feel fully comfortable with this concept. "Because" heads up subordinate clauses, which means if you have a clause that starts with "because," you must also have a main clause in your sentence. It is absolutely wrong to say that it is not a sentence just because it begins with the word "because." But if grade school or junior high school teachers tried to offer their students a grammatical explanation of when they could begin with because and when they couldn’t, it might sound something like this: “You may begin with because if your dependent clause is followed by an independent clause, but if your sentence consists of a single clause, you may not begin with because.”