One inconsistency that poses problems for writers and readers is a mixed structure, which 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, but instead it moves to another phrase followed by a dependent clause (a wake-up time that explains why I’m always tired in the evening), and what results is a fragment.

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.

(For information about subjects and predicates, see 31j and k; for information about independent and dependent clauses, see 31m.)