In order to be able to revise or even recognize mixed constructions in your writing it is important to understand what they are first. A mixed construction is created when a dependent clause, prepositional phrase or an independent clause is incorrectly used as the subject of a sentence.
So, let’s take a look at what it looks like when a dependent clause is incorrectly used as the subject of a sentence:
Because he works eleven hours every day
explains why he is always tired.
To be able to understand this example it is important to know what a dependent clause is first. A dependent clause is a group of words with a subject and a verb but which does not express a complete thought. For this reason, it is not a sentence and can’t stand alone. The dependent clause in this sentence is: Because he works eleven hours every day, and in this case this entire clause is incorrectly used as subject here. A revised version of this sentence could look like this:
Because he works eleven hours every day, he is always tired.
If you get rid of ‘explains why’ the clause ‘Because he works eleven hours every day’ is combined with an independent clause (He is always tired) and together they now form a grammatically correct sentence that expresses a complete thought.
The following sentence contains a mixed construction because, what’s called, a prepositional phrase is incorrectly used as the subject of the sentence.
By enlisting in the army
is a good way to see the world.
Prepositions are words like at, on, in, by, etc., and if a phrase starts with one of these words, this phrase is called a prepositional phrase. You create a mixed construction if you use this type of phrase as the subject of a sentence, which was the case here. ‘By enlisting in the army.’ is an incorrectly used.
After revision the sentence looks like this:
By enlisting in the army, you can see the world.
The prepositional phrase is still there but you now is the subject of the sentence.
Sometimes independent clauses are also incorrectly used as the subject of a sentence, like in the following example:
She was rich made her buy more than she needed.
An independent clause is a sentence with a subject and a verb that expresses a complete thought and that, therefore, can stand alone. However, in this case it is incorrectly used as the subject of a sentence.
She was rich is the independent clause here that was incorrectly used as a subject, and the sentence can be rewritten like this:
Being rich made her buy more than she needed.
Being rich is now the subject of the sentence and now the sentence works.