Introduce a complete list with comprising, consisting of, or composed of rather than including (which would indicate that the list is incomplete):

Incorrect: The English alphabet includes 26 letters (are there more than 26?)

Correct: The English alphabet comprises 26 letters

Correct: The English alphabet is composed of 26 letters

Woeful: The English alphabet is comprised of 26 letters

Correct: The English alphabet consists of 26 letters