Final answer:
In the sentence given, 'that' is an adjective clause marker (AdjC) and 'if' is an adverb clause marker (AdvC). The word 'so' is not a subordinating conjunction in this context and 'as' is not functioning as a conjunction, so neither are marked.
Step-by-step explanation:
To identify subordinate conjunctions and clauses, it's important to understand that a subordinate clause, which is dependent on the main clause to provide a complete thought, will begin with a subordinating conjunction. In the provided sentence, 'A system that took so long to build will probably need as much time, if not more, to truly adapt to the free enterprise system,' we can identify the subordinating conjunctions and underline the subordinate clauses accordingly.
The conjunction 'that' begins an adjective clause describing 'a system,' so it is marked as A) That - AdjC. The word 'so' is not a subordinating conjunction in this context, as it is part of the phrase 'as much time,' which is used for comparison rather than subordination. The conjunction 'if' introduces an adverb clause of condition and is marked as C) If - AdvC. Lastly, 'as' is not functioning as a conjunction here, so it should not be circled or marked as D) As - NC, which would denote a noun clause. Therefore, in the sentence, we have an adverb clause and an adjective clause, displayed as 'That - AdjC' and 'If - AdvC.