We put a group of words together to form a sentence. But not all sentences are made up of a group of words. A sentence must have a main clause or more than one main clause. There are as many clauses as there are finite verbs in a sentence. (The finite verb is the verb that changes with the person or number of the subject.)

A sentence:

• begins with a capital letter and ends with a full stop (period), a question mark, or an exclamation mark.

• has to meet the requirements for a sentence such as being able to stand by itself, and making sense. To ensure it does, the following point is important: The subject-predicate agreement must be observed:

EXAMPLE: That new car. (This is a subject but there is no predicate, so it is not a complete sentence.) Complete sentence: That new car runs fast. (= predicate in bold)

• expresses a complete idea as a statement or asks a question.

EXAMPLE: The sun rises in the East. / What is your name?

• may be a word or short sentence used to express a strong feeling such as surprise, excitement or anger.

EXAMPLE: You did it!

• can also be a combination of two or more clauses. One of the clauses must be an independent clause, and the other clause can either be an independent or a dependent clause. It is important to know about clauses in order to construct complete sentences.

• has two parts: a subject (noun or pronoun) and a predicate (a verb or a phrase) as explained below.

• can be one word or two words, and as long it can stand alone, its meaning is clear, and does make sense, it is accepted as a sentence.

EXAMPLE:
One-word sentence: Stop! Go!
Two-word sentence: Look out!
One-clause sentence: I cannot sleep.
Two-clause sentence: She cooks and I eat. (Joined by conjunction and)
The last sentence is made up of two clauses: She cooks; I eat. Each has a subject and a verb (subject: She / I; verb: cooks / eat) which most sentences must have.

• can be joined to another sentence without the use of a conjunction. We do it by using the present participle which is the –ing form of a verb: look – looking.

• can be made a negative sentence using –ing form of the verb, we put not in front of it.

EXAMPLE: Not finding a place to park, I decided to go elsewhere.

The forms of a sentence
There are four forms of a sentence as follow:
A statement: That hotel restaurant serves a buffet breakfast.
A question: Do you expect me to believe everything you said?
A command: Don't just stand there. Do something.
An exclamation: What a terrible waste of time!

Besides subject and verb, other parts that make a sentence are object and modifier (see below for explanation.