Subject
A canonical clause consists of a Subject followed by a Predicate. Subject is noun or phrase which comes before a verb or predicate and which perform the action of that verb or is described by it. A basic element in every clause is the subject which is composed of a noun (N) any determiner (Det) or any modifiers (Adj., Adv. + Adj.). N – person, animal, place, thing, or concept.
Example:
That boy repaired the chair.
My sister bakes cookies every Sunday.
Someone next door rang the bell.
The Subject is mostly realized by a noun phrase, but there are other possibilities too, most importantly a subordinate clause:
a. One of his friends called a doctor. (noun phrase as Subject)
b. That he was lying was obvious. (subordinate clause as Subject)
In canonical clauses describing an action the Subject will be associated with the semantic role of actor, or agent, as in (a). But many clauses don't express actions: we heard an explosion, for example, describes a sensory experience, and here the Subject is associated with the role of experience. There are numerous different kinds of semantic role that can be associated with the Subject: what the role is in a particular instance will depend on the meaning of the clause, especially of the verb.
Meaning therefore does not provide a reliable way of identifying the Subject. But this function has a good few distinctive grammatical properties which together generally make it easy to identify. Here are some of them.
Subjects are obligatory
My brother wears a green overcoat.
Wears a green overcoat is not a possible sentences.
This constituent may consist of group of words whose most important element denote a person (my brother, that stupid boy, the police)
Subject-Verb Inversion
In a declarative sentence, the Subject comes before the verb:
Declarative: David is unwell
When we change this into a yes/no interrogative, the Subject and the verb change places with each other. If an auxiliary verb is present, however, the subject changes places with the auxiliary:
Declarative: Jim has left already
Interrogative: Has Jim left already?
Position of the Subject
Subjective Pronouns
The pronouns I, he/she/it, we, they, always function as Subjects, in contrast with me, him/her, us, them:
I left early *Me left early
He left early *Him left early
The pronoun you can also be a Subject: You left early.
We can identify the Subject of the sentence by adding a so-called tag question to it. A tag question as he name implies, is a short question that is tagged onto a statement.
This teacher is smart, isn’t she?
The kids have arrived safely, haven’t they?
Your brother can be serious, can’t he?
B. PREDICATE
The other basic and necessary element of a clause is a predicate. The predicate is a unit of a sentence which function is to specify what the subject engaged in doing. The Predicate is realized by a verb phrase (VP). The verb (V) may require an object (He gave a gift.) and/or an indirect object (He gave me a gift.), or a predicative complement (It seems good.) The predicate may also include other elements such as adverb phrase (AdvP) with one or more adverbs (Adv), a prepositional phrase (PP), or a clause, etc. Now we will look inside the Predicate, and assign functions to its constituents. Recall that the Predicate is everything apart from the Subject.
Example:
The lady singing with a boy is.
My boyfriend gave me a bucket of flower.
Her son plays the piano.
My younger sister drinks milk before she sleep.
A predicate includes the verb, its complements, and may include adjuncts. Complement – a word, phrase or clause which is necessary in a sentence to complete its meaning (e.g., direct object, indirect object, or a predicative complement).
a. Verb
Verb is word or phrase that describes an action, condition or experience. In formal terms, we refer to the verb as the PREDICATOR, because its function is to predicate or state something about the subject. Notice that Predicator is a functional term, while verb is a formal term:
Form
Function
Verb
Predicator
b. Direct Object
Example: David plays the piano
In the sentence, the NP the piano is the constituent which undergoes the "action" of being played (by David as the Subject). We refer to this constituent as the direct object.
Here are some more examples of Direct Objects:
We bought a new computer.
I used to ride a motorbike. The police interviewed all the witnesses.
We can usually identify the Direct Object by asking who or what was affected by the Subject. For example:
We bought a new computer. Q: What did we buy? A: A new computer ( = the Direct Object)
The Direct Object generally comes after the verb, just as the Subject generally comes before it. So in a declarative sentence, the usual pattern is:
Subject – Verb – Direct Object
c. Indirect Object
The Direct Object is most often realized by an NP, as in the examples above. However, this function can also be realized by a clause. If there is a indirect object of a sentence, then the indirect object is placed between the verb and direct object. If a possible sentence of indirect object, then the existence of direct object into something that is absolutely in the sentence. Because, the indirect object cannot exist without the direct object. But not as a direct object, direct object can stand without indirect.
Example:
I threw him the ball.
John gave the boys the CDs.
My mother baked me a birthday cake.
d. Adjunct
Adjunct is a word, phrase, or clause which is not necessary in a sentence to complete its meaning (example: an adverb, a preposition phrase).
a. She spoke very clearly.
(adverb phrase as Adjunct of manner)
b. As a result of his action, he was fired.
(preposition phrase as Adjunct of reason)
c. They left the country last week.
(noun phrase as Adjunct of time)
C. PREDICATOR
Her son plays the piano
The Predicator is the function filled by the verb. The verb is the head of the verb phrase, and Predicator is the special term used for the Head of the verb phrase forming the Predicate of a clause. Thus above example play the piano is a verb phrase functioning as Predicate while play is a verb functioning as Predicator.
Eric lost his keys yesterday.
Recall that the Predicate in a sentence consists of everything but the Subject. Thus, in example Eric is the Subject and lost his keys yesterday is the Predicate. Inside the Predicate we distinguish the Predicator (the verb lose), the Direct Object (the NP his keys) and an Adjunct (the Noun Phrase yesterday).
Predicates are Verb Phrases and Predicators are always main verbs. There is little variability as regards the realization of Predicates and Predicators.