They will never solve the riddle<span />
The type of sentence given is a compound sentence. It is a compound sentence because it consists of two independent sentences: "I already said yes to someone else" and "I can't go to the dance with you". In order to link the two sentences, the conjunction "because" is used.
The sentence "Fustian writing is where you write pompous, bombastic nonsense." is illogical for the following reasons:
1. Fustian, like the sentence implies, means pretentious speech or writing.
2. Fustian writing does not refer to a place.
3. The word <em>where </em>is used to refer to a place.
4. Using the word <em>where </em>implies that<em> fustian writing</em> is a place, which is wrong.
Therefore, one can correct the sentence and say this instead: Fustian writing is when you write pompous, bombastic nonsense.