<span>I shall have learned what little
there is about greatness.</span>
I believe the correct answer is naive.
The author is trying to say that he was ignorant, and that he couldn't understand properly these new revelations. He was either too young or too stupid to understand such a thing, but he believes he will as he grows older.
Answer: The difference between a compound sentence and complex sentence is that a compound sentence has two independent clauses and a complex sentence has one independent clause and one dependent clause
You could use both as long as you use them correctly
