A clause is a group of words that contains a verb and its subject. There are two types of clauses – main clauses and subordinate clauses.
Main clauses
A main clause is a clause that can stand as sentence by itself.
A compound sentence contains two or more main clauses, because it is made up of two or more simple sentences.
Each of these simple sentences is a main clause.
Example:
Robots operate machines, and they solve many labour problems.
Robots operate machines and they solve many labour problems are both main clauses.
They are also simple sentences.
Main clauses are sometimes called independent clauses.
Subordinate clauses
Subordinate clauses are clauses that do not express a complete thought.
So they cannot stand by themselves.
Examples:
If technology will improve when robots can do the work while electronics will work after the system is complete.
None of the above clauses express a complete thought.
They are sentence fragments that leave the reader wondering then what?
Subordinate clauses are introduced by subordinating conjunctions such as if, when, while, and after.
Other examples of subordinating conjunctions:
Although because so that until
As before than whatever
As if in order that though wherever
As long as provided till whenever
As though since unless where
Now we can understand a complex sentence better.
We have said that it contains one main clause and one or more subordinate clauses.
Main clause, subordinate clause
The bell started ringing before we were out of bed.
The battery needs recharging so that it can work tonight.
The subordinate clause can sometimes appear before the main clauses.
Examples:
When the power failed, the computer stopped.
Before you know it, your flat screen television will be stolen.
The subordinate clause can also sometimes appear in between the sentence.
Example:
The medicine man, who knew many tricks, cheated the man that he had been bewitched.
Types of subordinate clauses
Subordinate clauses may be used in sentences as adjectives, adverbs and nouns in complex sentences.
Such clauses are called adjectival, adverbial and noun clauses respectively.
They add variety to one’s writing.
They can also make one’s writing more interesting by adding details.
Examples:
Without subordinate clause: The bushman told us about the hidden cave.
With subordinate clause: The bushman, who knew the forest well, told us about the hidden cave.