The document discusses clauses and subordinate clauses. It provides examples of joining two sentences into one sentence using subordinate clauses, and rearranging the order of the clauses using commas. The main points are:
- A clause is a part of a sentence, and can be either a main clause or subordinate clause.
- Subordinate clauses add extra information to the main clause and cannot stand alone.
- Subordinate clauses can be moved around and placed before or after the main clause by using commas.
- Multiple sentence structures can be formed by combining the two given clauses in different ways using commas and subordinate conjunctions.