An independent clause or main clause is a group of words that include a subject and a verb. It is a complete sentence that expresses a complete thought. This means it can stand alone as it is not dependent on another clause to form a sentence. A sentence must have a main clause.
The following are complete statements and are therefore main clauses.
- All of us sat beneath a shady tree.
(Subject: All of us; action verb: sat)
- You are my best friend.
(Subject: You; linking verb: are)
- My uncle has a mongoose with a long body and tail.
(Subject is my uncle. The verb has can be an action verb or a linking verb. It is used here as a linking verb.)
Each of the following is a group of words that does not qualify as an independent clause. Each one is an incomplete statement and it cannot stand on its own as an independent clause.
- That we have been buddies.
(This is not an independent clause. It is a that-clause introduced by the relative pronoun that.)
- When all of us sat beneath a shady tree
(The relative pronoun when introduces a relative clause. A relative clause is not an independent clause.)
- My uncle who has a male mongoose with a long body and tail
(This is not a complete clause/sentence. The subject my uncle is followed by the relative clause who has a male mongoose with a long body and tail. The subject must be followed by at least a verb to make a complete clause.)
Correction of the incomplete statements above.
- They know that we have been buddies.
(They said is a main clause joined to the that-clause fo form a complete sentence.)
- When all of us sat beneath a shady tree, we could feel the soft cool grass.
(The main clause we could feel the soft cool grass is depended on by the relative clause beginning with when to form a complete sentence.)
- My uncle, who has a male mongoose with a long body and tail, is looking for a female mongoose.
(The relative clause is within the main clause which is my uncle is looking for a female mongoose.)