What is a sentence?
All academic writing is based on sentences. In other forms of communication it is often acceptable to speak or write in any form that gets the meaning across; however, in academic writing your sentences have to be correct. There are many definitions of a sentence, but the following one expresses the meaning quite clearly:
A sentence is a group of words that expresses a complete thought.
Here are some examples:
Sentence: Jack ran.
Sentence: Jill ran.
Sentence: Jack and Jill were late.
Sentence: Jack and Jill ran up the hill to go to university and to fetch a pail of water on the way back.
As you might have noticed, a sentence can be short or long or anything in between, but it has to fulfil the following requirements.
1. It has to have a subject (noun or pronoun). This is usually the person, thing or concept that does the action in the sentence and is called the actor. It tells who or what the sentence is about.
Example:
Jack ran.
Jill ran.
Jack and Jill ran.
The hill is steep.
The well has good water.
Running is good for you.
2. It has to have a predicate (verb or verb phrase). This is usually the action that the actor does. It describes what the subject is or is doing.
Example:
Jack ran.
Jill ran.
Jill is taller than Jack.
The words "ran" and "is" are the verbs because they tell us what Jack and Jill are up to.
3. It has to express a complete thought.
That means that the sentence should supply enough information so that you are satisfied. If the sentence reads like the following examples, you would know that something is missing (I hope):
Because Jack and Jill were running up the hill.
Jack and Jill are.
Running up the hill in order to go to university.
Here are some more examples of subjects and verbs in a complete sentence:
| Subject | Verb | |
|---|---|---|
| Jill | runs | to the well. |
| The well | is located | on top of a hill. |
| It | is | full of water. |
| Jack and Jill | are exhausted | when they get to the well. |
| Jill | shouts. | Be careful! |
In a sentence the subject comes after the verb. However, sometimes the roles are reversed, i.e. in questions:
Then it looks like this:
| Verb | Subject | Verb | |
|---|---|---|---|
| Are | Jack and Jill | running | up the hill? |
| Don't | they | know | that it is exhausting? |
To find the subject, ask yourself:
"What word is the sentence describing?"
"Who or what is doing the action in the sentence?"
To find the subject in a question, turn the question into a statement.
- Jack and Jill are really running up the hill.
- They don't know that it is exhausting.
To find the verb ask yourself: "What did the subject do?"
- Jack and Jill ran up the hill.
- They don't know that it is exhausting.
There are two basic kinds of sentences. They are often called "clause" (there is no intended relation to Santa!).
The first kind is called an independent clause:
An independent clause is a complete sentence because it has a subject and a verb and expresses a complete thought.
The second kind is called a dependent clause:
A dependent clause has a subject and a verb but does notexpress a complete thought. It needs to be combined with an independent clause to be elevated to real sentence status.
Here are some examples of independent clauses.
Independent clause:
- The moon was big and round that night.
- The frogs had a croaking contest.
- Aunty Jane had a wart on her nose.
- You fetch a pail of water.
- The fairy godmother supplies the glass slippers.
As you can see, they are all good sentences with subjects and verb forms, and they express a complete thought.
The relative of the independent clause is the dependent clause.
It is usually incomplete because of the dependent marker (words such as while, because, since) which is also called a subordinating conjunction.
Even though you might have a perfectly perfect sentence with a subject and a verb, the very presence of the dependent marker spoils all the fun. Suddenly the sentence loses its status and is downgraded to a dependent clause. It can look like this:
Dependent clause:
- Because the moon was big and round that night.
- While the frogs had a croaking contest.
- Even though Aunty Jane had a wart on her nose.
- When you fetch a pail of water.
- Until the fairy godmother supplies the glass slippers.
As you can see, these sentences should not be left alone because they simply don't complete the idea. However, if you combine them with an independent clause, everybody is happy again, and you get a complex sentence.
A complex sentence consists of at least one dependent and one independent clause and can look like this: (the dependent part is underlined)
- Because the moon was big and round that night, the fairies had to close their windows.
- While the frogs had a croaking contest, I couldn't get any sleep.
- Even though Aunty Jane had a wart on her nose, nobody knew she was a wicked witch.
- When you fetch a pail of water, you had better be careful not to fall down.
- Until the fairy godmother supplies the glass slippers, Cinderella won't even think about going to the party.
Of course you can reverse the order of the dependent and independent clauses; you'll still have a complex sentence. Then it looks like this:
- The fairies had to close their windows because the moon was big and round that night,
- I couldn't get any sleep while the frogs had a croaking contest.
- Nobody knew she was a wicked witch even though Aunty Jane had a wart on her nose.
- You had better be careful not to fall down whenyou fetch a pail of water.
- Cinderella won't even think about going to the party until the fairy godmother supplies the glass slippers.
If you have been very perceptive, you might have noticed that the punctuation varies according to which part of the sentence comes first. There is more information in the punctuation section on this phenomenon.
By now you might have started to wonder what happens if you put two independent clauses together. Well, if you put two independent clauses together, you'll get one big and happy compound sentence.
A compound sentence can look like this:
- Cinderella really wants to stop cleaning out the ashes, but her stepmother has other ideas.
- The two stepsisters are looking forward to going to the party, and Cinderella sits in the corner and sulks.
- Everybody knows that mice can't sew dresses; however, the fairy godmother has always been the other option for getting clothes.
- The glass slippers look absolutely gorgeous; nonetheless, they are killing your feet.
The parts of a compound sentence could stand alone, but then who wants to be alone all the time? Writing too many short sentences can sound very abrupt. The tricky part when combining independent clauses is the punctuation. However, that will also be dealt with in the punctuation section.
There are other kinds of combinations of dependent and independent clauses with fancy names. If you want to find out more about them, you could enrol in the STUDY LINK Subject "Grammar Essentials for Writing at University".