The
grammatical subject of a sentence is the noun, noun phrase or pronoun
that comes before the verb. The subject is normally described as the
agent (do-er) of an action:
All
the children
ran away.
He
said I was stupid.
However,
some verbs serve a linking function rather than expressing an action
(see linking verbs). In sentences with linking verbs, something is
said about the subject:
Belinda
is a drug addict.
I
became a teacher 10 years ago.
When
the verb is in passive form, the subject of the sentence is the
recipient of the action:
Vicki
was
bitten by a poisonous spider.
English
demands that all sentences (except some exclamations, such as 'How
nice!') have a subject. In some sentences, 'there' or 'it' acts as a
dummy subject.