Faulty sentence structure poses problems for both writers and readers. A mixed structure results from beginning a sentence with one grammatical pattern and then switching to another one:

The sentence starts out with a subject (The fact) followed by a dependent clause (that I get up at 5:00 AM). The sentence needs a predicate to complete the independent clause (37a), but instead it moves to another phrase (a wake-up time) followed by a dependent clause (that explains why I’m always tired in the evening), and what results is a fragment (Chapter 47).

Deleting a wake-up time that changes the rest of the sentence into a predicate.

Deleting The fact that turns the beginning of the sentence into an independent clause.

Here is another example of a mixed structure:

The dependent clause beginning with Because is followed by a predicate (beginning with explains) without a subject. Deleting explains why changes the predicate into an independent clause.