quadrennially is an adverb, so you might do things quadrennially. Quadrennium, like most words ending in "ium" is a noun - probably mostly used in the sense of "4th anniversary", or "4th year".
a quadrennial
because she had back problems and her doctor said if she does gymnastics again she won't be able to walk.
you mean what you mean
It mean what you don't what does it mean.
Mean is the average.
What does GRI mean? What does GRI mean?
The correct usage is "what DOES it mean"
The haudensaunee mean irguios
he was a mean person who lived with mean people in a mean castle on a mean hill in a mean country in a mean continent in a mean world in a mean solar system in a mean galaxy in a mean universe in a mean dimension
as you do
No, but sometimes "average" means "mean" - when it doesn't mean median, geometric mean, or something else entirely.