Basic Distinctions in English Grammar

What is a sentence? How is it different from a clause and a phrase?

A sentence is a group of words that makes complete sense. A clause is a group of words, which may or may not make complete sense. When a clause makes complete sense, it is called the independent or the main clause. A clause that does not make complete sense is called the dependent or the subordinate clause. A phrase is a group of words, which does not make complete sense.

E.g. Sam teaches English (a sentence, and an
independent clause).
Sam loves English, which is not his first language (a sentence that consists of an independent clause, "Sam loves English", a dependent clause, "which is not his first language", and a phrase, "his first language").




How is a phrase different from a clause?

A phrase is a group of words, which makes incomplete sense. It does not contain a subject or a finite verb. A clause is a group of words, which may or may not make complete sense. It contains a subject and a finite verb.

E.g. Sam loves English, which is not his first language.
There are two clauses in this sentence, viz., "Sam loves English", and "which is not his first language". In "Sam loves English", "Sam" is the subject, and "loves" is the finite verb. In "which is not his first language", "which" is the subject and "is" is the finite verb.
There is a phrase in this sentence, viz., "his first language". It does not contain a a subject or a finite verb.





What is the distinction between a subject and a predicate?
A sentence consists of a subject and a predicate. The subject is what one speaks about. The predicate is what one says about the subject.

E.g. Sam (the subject) teaches English (the predicate).

The subject is usually a noun or a noun phrase.

E.g. Sam (noun) writes poems.
The man (noun phrase) writes poems.

The predicate is the verb followed usually by the object and the complement.

E.g. Sam writes poems regularly (verb+object+complement).




What is the difference between a subject and an object?

The subject governs the verb. The object receives the action of the verb.

e.g. The lion killed the deer.
In this sentence, "the lion" is the subject that governs the verb "killed". "The deer" is the object of the verb "killed".




How is the active voice different from the passive voice?
In the active voice, the subject performs an action. In the passive voice, the subject undergoes an action.

e.g. The lion killed the deer (the subject, "the lion" performs an action, therefore the voice is active).
The deer was killed by the lion (the subject, "the deer" undergoes an action, therefore the voice is passive).




What is the difference between a transitive verb and an intransitive verb?

A transitive verb transmits action from the subject to the object. An intransitive verb does not transmit action, as it does not have an object.

e.g. I laid the book on the table (the verb "laid" transmits an action from the subject "I" to the object "the book", therefore it is transitive).
I lay in bed all day (the verb "lay" transmits no action, therefore it is intransitive).




What is the difference between a main verb and an auxiliary verb?

The main verb is the final verb in a verb phrase. The verb phrase is the sequence of an auxiliary verb and a main verb. The auxiliary verb helps the main verb.

e.g. Sam has taught English before ("has taught" is the verb phrase, "has" is the auxiliary verb, and "taught" is the main verb).




What is the difference between a finite verb and an infinitive?
The finite verb shows tense, and agrees in person and in number with the subject. It could be a single verb or a verb phrase. The infinitive does not show tense, and remains unaffected by person and number. The infinitive is a sequence of "to" followed by the base form of a verb. The base form of a verb is one which has not changed according to tense, number and person.

E.g. Maria loves to sing ("loves" is the finite verb, "to sing" is the infinitive).

When the finite verb in the previous example changes in tense, and in number, and in person, as in the following examples, the finite verb reflects these changes, while the infinitive does not.

e.g. Maria loved to sing.
       They love to sing.
       I loved to sing.




What is the distinction between the present participle and the gerund?
Both the present participle and the gerund are "-ing" forms of a verb. The present participle is used to form continuous tenses, and to act as an adjective. The gerund is used in the place of a noun.

e.g. He was walking towards me ("walking" is a present participle in the verb phrase, "was walking", which is in the past continuous tense).
After the accident, I had to use a walking stick ("walking" is a present participle, which functions as an adjective, which qualifies the noun "stick").
Walking is a good exercise ("walking" is a gerund, as it functions as a noun, which governs the verb "is").