The phrase "a vital phase" is correct and usable in written English.
It can be used to describe an important stage or period in a process or development.
Example: "The project is entering a vital phase where key decisions will determine its success."
Alternatives: "a crucial stage" or "an essential period".
For Israel, the business of recruiting informers is a vital phase of the fight against terrorism.
We are heading into a vital phase of the project that will determine whether Amref's work really makes a lasting impact.
As an incurable optimist, I'm hoping this will be the year we look back on as a vital phase of America's recovery from its post September 11 insanity.
At a vital phase of that encounter in Cardiff which England so narrowly saved, Pietersen played a shot of the starkest irresponsibility as he top-edged a sweep to a ball outside off-stump from Nathan Hauritz.
In 2012 Europe will deliver its input to that vision in the form of a European strategy for particle physics to be presented to decision-makers in Brussels in the autumn.The answer the world has been waiting forMeanwhile, across the Atlantic, American particle physicists will be entering a vital phase as the Fermi National Accelerator Laboratory seeks government approval for its next big project.
His solo piano work marks a vital phase in the transition from ragtime to jazz, but Morton also incorporated many of the rhythmic ideas of his Hispanic Creole heritage.
He is in a vital transitional phase.
Many see the technology's rise as a vital new phase in the internet economy one that is, arguably, even more transformative than the first.
He will be invaluable as the government embarks on the next, vital phase of its mission to restore our economy to growth and reform our public services".
"What we must do now is make sure everything is done to help in this vital phase of dealing with the floods.
"He will be invaluable as the Government embarks on the next, vital phase of its mission to restore our economy to growth and reform our public services".
