Which part of the following sentence is a subordinate clause?
Nineteen Eight-Four, which was published in 1949 as Orwell suffered with tuberculosis, gave a gloomy account of a dystopia of repression and propaganda.
A subordinate clause is one which functions as an adjective, and adverb, or a noun. It expressed an idea that is less important than the main clause. It can not stand on its own as a sentence.
In this sentence, the subordinate clause is
"which was published in 1949... tuberculosis."
This clause gives us more information about the circumstances of the publication, but could not stand alone as a sentence.
The main clause is "1984 gave a ... propaganda." That tells us the main point of the sentence. The subordinate clause simply gives us more information.
The subordinate, or dependent clause, is "which was published in 1949 as Orwell suffered with tuberculosis." This is an adjective clause. Within the adjective clause lies an adverb clause "as Orwell suffered with tuberculosis." Which is the subject and was published is the verb of the first subordinate clause. Orwell is the subject and suffered is the verb of the second clause.
The Main Clause or the Independent Clause which makes complete sense when it stands all by itself is:
'Nineteen Eighty-Four gave a gloomy account of a dystopia of repression and propaganda.'
The sub-ordinate clause or the dependent clause which will not make complete sense by itself is:
'which was published in 1949 as Orwell suffered with tuberculosis'
Since this sub-ordinate clause is within parenthesis, that is, enclosed within commas it is a 'non-defining' relative clause. The information given in this sub-ordinate clause is only additional information to the information supplied by the independent main clause.