This is a general problem faced by the students studying clauses. I usually tell my students to learn all the subordinating conjunctions if they feel it difficult to recognise a subordinating clause on the basis of the meaning it conveys.
The following conjunctions immediately clear to you that the clause formed by them is subordinate in meaning to the Principal Clause.
who, whom, whose, which, that, as, as soon as, no sooner….than, till, until, unless, if, supposing that, in case, even if, when, whenever, where, wherever, whence, why, because, what, whatever, though, although, as if, as though, so far as, as far as, etc.
Examples:
The boy who is wearing a red shirt is my friend.
In the above sentence, you are now able to find the subordinating conjunction ‘who’. It is followed by its predicate (verb and other words/phrases). So the above sentence is a complex one.
If you want to pick out the subordinate and principal clause, you may do like this:
How can I identify the type of subordinate clause in a sentence? I mean, I know the definition but fail to identify the clause type. Is there an easy way out?
(i) The boy is my friend. (Principal Clause.)
(ii) ‘who is wearing a red shirt is the subordinate clause in the above sentence.
Actually, in the sentence ‘The boy who is wearing a red shirt is my friend.’, there are two sentences that are joined together.
A boy is wearing a red shirt.
He is my friend.
After joining the above two simple sentences, the complex sentence is ‘The boy who is wearing a red shirt is my friend.’
