The virtue of that woman was something that will always be admired.
she lost her virtue in the city.
A number of claims have been made on behalf of virtue epistemology.
I think it's more correct to say "Is gratitude a vanishing virtue?" or "Does gratitude seem to be a vanishing virtue?"
The girl in my class was a virtue in a moral excellence in a particular class such as math.
That sentence is not correct. If you want to keep it as a question as to whether gratitide is less common then it should be "Does gratitude seem to be a vanishing virute?" or if it is meant as a statement the it is "Gratitude is a vanishing virtue."
She was a paragon of virtue.
civic vertue
The sentence should be punctuated as: Patience - it's a virtue not often seen on the freeway at 5:15 pm.
Experience is the knowledge by virtue of committed mistakes.
You can say something like "...by virtue of the fact that.." For example: "I know the mechanics of a sentence by virtue of the fact that I am an English teacher." By adding the letter "s" you are defining virtues as "the good thing about," so you can discuss the virtues of skim milk, inter alia.
there are many published accounts of this incident, one version may have the virtue if being true
Bravery is a virtue that not a lot of people possess at the moment.