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Basic Grammar and Punctuation

An AARC writing resource

About Complex Sentences

Once you can identify a basic sentence, you can join two or more sentences into complex sentences.

Two or more sentences can be combined with a subordinating conjunction that explains the relationship between each idea. For example:

Simple Sentences - He studied hard. He wanted to go to medical school. He suffered from arthritis.

Complex Sentence - He studied hard because he wanted to go to medical school as he suffered from arthritis.

Complex Sentence - Even though he suffered from arthritis, he studied hard because he wanted to go to medical school.

Notice how the subordinating conjunction adds additional meaning to the sentence. The last two sentences tell us why he studied.

Some Common Subordinating Conjunctions:

After

Before

So that

Whenever

Although

Even though

Though

Where

As

If

Unless

Whereas

As if

In order that

Until

Whether

Because

Since

When

while

A subordinating conjunction is sometimes called "a heart word" because it turns two sentences into one. Even though both sentences contain a subject and verb, one becomes dependent on the other and cannot stand alone. One sentence becomes the explaining idea for the main idea.

How to fix Complex Sentences:

Any time you see "a heart word" like the ones above, check that your sentence doesn't leave a question remaining. For example:

Wrong - When he came late to class. (What happened when he was late?)

Right He forgot to give the teacher his homework when he came late to class. 

Wrong - After she noticed it missing. (What happened when she noticed?)

Right - The teacher asked for his homework after she noticed it missing.

Wrong - Because they knew the test would be difficult. (What happened as a result?)

Right - The students studied furiously because they knew the test would be difficult.

Punctuation depends on the location of the "heart word" or subordinating conjunction:

1) If the subordinating conjunction comes in the middle or at the end of the sentence – no comma is required. For example:

Wrong – School is not all about studying, since there are lots of clubs and fun activities on campus.

Right – School is not all about studying since there are lots of clubs and fun activities on campus.

2) If the subordinating conjunction comes at the beginning of the sentence – a comma comes at the end of the dependent clause. For example:

Wrong  Even though I would rather go hiking I went to the library to study.

Right – Even though I would rather go hiking, I went to the library to study.