Yes the sentence “I’m sorry I can’t see what you mean” makes sense
A synonym for "flat" would be "Deflated" or "Low".
The type of sentence for the sentence “When night fell, she
went out to look at the stars.” is complex.
To add, a complex sentence contains an independent
clause and at least one dependent clause. An independent clause can stand alone
as a sentence and makes a complete thought and a dependent clause
cannot stand alone, even though it has a subject and a verb.
The answer is B. Inferences.