Have you ever read a sentence, one you may have written yourself, in which the parts do not seem to fit together?  If you have (which is almost a certainty), then you came across a mixed construction.   The following examples and exercise will help you identify, understand, and analyze mixed constructions.

Confusing: The purpose of the program allows a student to solve a quadratic equation interactively.

We understand what the writer is trying to say, but the sentence is confusing. Why?

1. “The purpose” of anything never simply “allows.”Revision 1: The purpose of the program is to allow a student to solve a quadratic equation interactively.This revision is correct, but it is wordy.
2. Who (or what) does the action in the sentence? In other words, who (or what) is the agent?Revision 2: The program allows a student to solve a quadratic equation interactively.If we make “The program” the doer of the action, then a program certainly “allows” a student to solve a quadratic equation.

   Better yet,

   Revision 3: The program solves a quadratic equation interactively.

   In Revision 3, the agent is the grammatical subject, and what the agent does (solves) follows as the main verb of the sentence.

3. If we make “a student” the agent, then we have a sentence like Revision 4.Revision 4: A student solves a quadratic equation interactively by using the program.

HOW DO YOU REWRITE CONFUSING SENTENCES TO MAKE THEM CLEARER?

There really are no firm “rules” to correct confusing sentences (or sentences with faulty predication). The best we can do is think and follow some general guidelines to improve their readability.

1. Determine who the “main character” in the sentence is. The “main character” is usually the person who does the action. Sometimes we call this “person (or thing) who does the action” the agent. Start the sentence with the person who does the action. In other words, start the sentence with the agent.
2. Determine what the agent is doing. What the agent is doing is usually stated as the main verb. Look for verbs that actually say something, strong verbs, rather than the verb “to be.”
3. If there are embedded clauses within the sentences, do the same with those clauses.

Confusing: The reason for Smith’s firing is because he lied in his employment application.

Revision 1: Smith was fired because he lied in his employment application.

Revision 2: The reason for Smith’s firing is his lying in his employment application.