It’s time to move on to complex sentences. Unlike compound sentences, which combine two complete thoughts, complex sentences combine one complete thought with one incomplete thought.

Complete Thought + Incomplete Thought = Complex Sentence

And the order does not matter. We can put the complete thought at the beginning or at the end and still have a complex sentence. The only difference it makes is in the punctuation, explained below.

SAMPLE LESSON

So let’s see what this looks like with a few examples.

This example begins with a complete thought, “Galileo was famous.” It ends with an incomplete thought, “because he developed the first telescope.”  Now if we flip the order of the sentence and put the incomplete thought first, then the punctuation changes.

Notice we put a comma after the incomplete thought. That is because incomplete thoughts are always attached to the predicate, making it an inverted sentence. The comma is a handy way to show this.

Much like compound sentences which are combined using conjunctions or connective adverbs, complex sentences are combined using subordinate conjunctions.

In the examples above, the subordinate conjunction is “because.” If we were to take out “because,” “he developed the first telescope” would actually be a complete thought. As soon as we put it in, however, it can no longer stand alone. It becomes dependent or subordinate to the rest of the sentence. Without the addition of “Galileo became famous,” “because he developed the first telescope” would not make sense. It would leave us wondering what else was meant to be said.

This brings us to a few additional terms. When talking about incomplete thoughts in the context of complex sentences, we can also call them dependent thoughts or subordinate thoughts. Likewise, complete thoughts can also be called independent thoughts. In order to have a term that opposes subordinate, my students and I also call them bossy thoughts.

No matter the terminology, the point is the same. One of the thoughts can stand alone; the other cannot. By putting them together, we end up with a complex sentence.

Diagrams of complex sentences always start off with the complete thought on top. We diagram this in the regular way. Then, we diagram everything else but the subordinate conjunction as if it were a complete thought just beneath it. Finally, we attach the two thoughts with a diagonal dotted line from verb to verb. Just make sure to capitalize the first word of the sentence so readers know whether the sentence is inverted or not.

PRACTICE SENTENCES

Renaissance scientist Galileo Galilei (1564-1642) will be the focus of these practice sentences. He was a controversial person in his day because he pushed the boundaries of scientific discovery in a way that challenged the Church, ultimately leading to conflict. Let’s take a quick look at what happened and practice complex sentences as we do so.

This sentence has a direct object phrase, which needs to be placed on a pedestal. Many direct object phrases begin with the word “that.” If “that” is not included, and often it is not, then simply put an “x” on the horizontal line on top of the direct object phrase.
Note that “out of” is a compound preposition, so both words go on the same line.

Sadly, Galileo’s story is not the most flattering for the Church. Its stubborn resistance to heliocentrism reflects a complex insecurity. At stake was not only the Church’s credibility on scientific matters but on theological ones as well, or so they thought. If they could get the galaxy backwards, then might they also get a lot of other things backwards?

And so, Galileo was compelled to recant. As a devout Catholic, he preferred to maintain his ties with the Church than to push his theory forward. Perhaps he knew that time would allow the Church, as well as the rest of the world, to realize he was right about heliocentrism—and that a True worldview could never undermine the authority of the Church.