A well written conclusion sentence sums up or restates the main idea of the paragraph that preceded it.
"They both have great humor" is a sentence.
Yes, but the sentence may not sound so great...
Example sentence - He found records indicating his great, great, great grandfather was a colonel in the military.
That is a great idea.
That's a great hat. Wow, that's a great hat!
You can construct a great sentence.
That is a great outfit you have on! What a great birthday I had!
Nobody else can give you a "great" sentence - we don't even know what you're writing about!
Mother creates great cupcakes.
The Great Pyramids were great!
Thank you for your GREAT example. That was a GREAT meal!
Peter the Great was a Russian czar.