Unfortunately Santa isn't coming this year.
The word "unfortunately" is not an adverb in this sentence. It is actually an adverbial phrase used to convey a feeling or sentiment.
The book was, unfortunately, marginally annotated.
Yes. Example: Unfortunately, I forgot to get milk while I was grocery shopping.
Some animals are unfortunately transitory.
His last act was unfortunately an ignoble one.
This sentence is tantalizingly short.
It is a sentence modifier - it limits or qualifies the sense of another word,
we unified the groups
Unfortunately, I didn't realize what that actually meant...
Your penis is very short if you have to ask this.
I am awesome.
A+ = short