Clauses
Clauses can also cause errors in sentence structure. A clause is a unit or group of words ranking below a sentence, but still consisting of a subject and a predicate. Remember that a predicate is the verb and all the words that follow in the sentence and that a sentence is not considered complete unless it has both a subject and a predicate.
An independent clause is a clause that has a subject and predicate and can stand alone as a complete sentence. A dependent clause is a clause with a subject and a predicate but cannot stand alone. If a dependent clause is standing alone, it will be a fragment, which is an incomplete sentence. Thus, a dependent clause must be attached to an independent one.
Let's look at an example of a dependent and independent clause. This sentence:
Molly was studying for her math exam.
is an independent clause since it has a subject, a predicate, and can stand alone. However, if you add a conjunction, which is a word used to connect phrases, the clause becomes dependent.
While Molly was studying for her math exam.
is not a complete sentence. It has a subject and predicate but needs to be attached to an independent clause.
While Molly was studying for her math exam, the fire alarm went off.
Adding the independent clause 'the fire alarm went off' makes the whole sentence now complete. So, to identify errors within clauses, check for dependent clauses standing alone. Also, watch out for conjunctions that might turn an independent clause into a dependent one.
Parallel Structure
Lastly, sentence structure greatly relies on having parallel structure, which is the consistent format of words and phrases within a sentence. What this means is that the words and phrases in each sentence should follow the same pattern. For instance:
My sister loves to hike, swim and skiing.
In this sentence, the pattern in the list is in the infinitive action word. 'To hike' and 'swim' are in the infinitive form. But, 'skiing' is not. To make this sentence parallel, change it to:
My sister loves to hike, swim and ski.
Sometimes parallel structure can be larger than a short list. For example:
The teacher told the students that they should study for the exam, that they should eat a healthy breakfast the day of the exam, and to do some practice problems.
This is a longer sentence, but still needs to be parallel. In this case, 'to do some practice problems' does not follow the structure of the rest of the sentence. Instead make it:
The teacher told the students that they should study for the exam, that they should eat a healthy breakfast the day of the exam, and that they should do some practice problems.
Now, this sentence is parallel. To avoid errors in your own writing, be sure that all your words and phrases are parallel.