There are different types of sentences in the English language depending on what their structure is. A simple sentence is one that consists of only one clause with a single subject and predicate this might be something very simple such as ‘Bill threw the ball.’ On the other hand complex sentences are ones that include one or more subordinate clauses.
A subordinate clause is typically introduced by a conjunction and forms part of the main clause. A subordinate clause is dependent upon the main clause. An example of a complex sentence is: ‘The teacher returned the homework after she noticed the error.’