Good writing does not exist without good sentences. Below are some of the more common problems with sentences written by students.

Mixed Construction: In general, a mixed construction occurs when a student begins one sentence and ends with another. Problems can occur on a grammatical level, when the mixed construction leads to improper subject-verb agreement or pronoun reference, or they can occur purely on the level of logic, where the sentence is technically correct, but makes no sense. For example:

Incorrect: For most people who eat veal, they don't think about where it came from.

Correct: Most people who eat veal don’t think about its origin.

Subject-verb Agreement: Often, an intervening phrase or clause can lead to a lack of agreement between subject and verb. Correctly identify the subject and make sure the verb agrees in number. For example:

Incorrect: One of the men who live in trailers want to move to a house.

Correct: One of the men who live in trailers wants to move to a house.

Misplaced Modifiers/Split Infinitives: Modifiers need to be close enough to the things they modify to prevent misunderstandings or lack of clarity. Infinitives with a modifier between "to" and the verb are often misunderstood.

Incorrect: After completing the exercise, modifier use will be better understood.

Correct: After completing the exercise, students will better understand how to use modifiers.

Incorrect: I want to smoothly drive home.

Correct: I want to drive home smoothly.

Lack of Parallel Construction: Parallel ideas should be expressed with similar phrasing. Parallel construction, or its absence, can occur on many levels, from that of individual words to that of entire phrases and sentences.

Incorrect: To be or living longer, that is the question.

Incorrect: ‘Tis a far, far better thing that I do, than I have done before, and I will rest better, too.