Understanding the Main Clause and Subordinate Clause

Main Clause is parents and subordinate clause is children. 
A father is an independent one who lives by his own earning,  he can buy the dress he likes,  he can go wherever he likes. Similarly a main clause is one which is independent and can stand alone with complete meaning. But what about children?  They depend on their parents for food,  education,  dress,  safety and so on.  They need support and cannot stand alone. The same applies to subordinate clause that cannot stand alone and cannot give complete meaning without depending on the Main clause. If the father is the engine in a train,  children are the carriages.  Carriages cannot run alone and they need to be chained with the engine. Likewise,  a subordinate clause needs to be attached to the main clause with a conjunction that is actually the chain for binding both.

Example :
As she was sick,  she did not attend the meeting.

Main Clause : she did not attend the meeting.
Subordinate clause : As she was sick

If you just say “As she was sick” and leave it alone,  can it make a complete sense?  No.  That’s why it is called, subordinate clause.  Note that it has the conjunction “as”. So the students can simply differentiate and understand that main clause has no conjunction but subordinate clause has conjunction.

Conjunctions in English : though,  as, since,  if, unless,  that, what, where, why,  when, who, whether, how,  how long,  how many,  how much, etc.
(think why but,  so, and...  are not given here)

Special issue :
Many students identify the main clause wrongly particularly when the conjunction ‘that’ is used in the sentence. They make a division in the sentence after the conjunction ‘that ‘ just because they always read so wrongly. 

Example :
He said that / he was not aware of the incident. (wrong division)

He said / that he was not aware of the incident. (right division)

Answer :
main clause – he said
Subordinate clause -- that he was not aware of the incident.

Explanation :
You may think that “he said” does not make complete sense. But ask a specific question – who said so? The answer is – he said. Doesn’t it make  a complete sense?  Further,  the actual sentence is “he said the fact that he was not aware of the incident “ and we generally omit “the fact” and think that “he said” is incomplete.  Finally,  can you tell me any sentence that ends with a conjunction? No.  You can’t . If you say, “he said that” is a clause,  how can conjunction come in the end?  Conjunctions are used only in the beginning and middle,  never at the end.

In the exam,  they will give a sentence and you should underline only the main clause in part II,  question no. 1 and underline only the subordinate clause in part II,  question no.2. 

Simple step to score 6 out of 6 marks:
Step 1: make a division first by a slash (if the conjunction comes in the middle,  division should be before the conjunction)

Step 2: Look for the conjunction.  If a divided part has conjunction,  it is main clause.  If the divided part has no conjunction,  it is subordinate clause.  Now underline accordingly as asked.

Some more examples for you:
Underline the main clause:
1.I don’t know why he is absent today. 
Answer: I don’t know why he is absent today.

2.My teacher told me that she would not excuse next time.
Answer : My teacher told me
3.We doubt whether he will join with us today.
Answer : We doubt
Underline the subordinate clause :
1.Everyone knows where he was born.
Answer : where he was born.
2.Though she is brilliant,  she could not answer any question.
Answer : Though she is brilliant
3.Parvathi admitted that she loved Aadhi.
Answer : that she loved Aadhi.
Exercises for you:

Underline the main clause:
1.You think that I did that.
2.When I was a child,  I was so innocent.
3.Since it is raining,  we have to cancel the trip.
4.He explained how he managed the situation.
5.I saw a student who made me think of my school days.
Underline the subordinate clause :
1.Do what I say.
2.Leave me alone if you really love me.
3.Tell me what you are thinking in your mind.
4.I don’t know how long you have been waiting here for me.
5.My father said that he would meet my teacher next week.