The phrase "a key rules" is not correct in English.
Did you mean "key rules"? You can use "key rules" when referring to important or fundamental guidelines that are essential in a particular context.
Example: "Understanding the key rules of the game is crucial for any player who wants to succeed."
Alternatives: "essential rules" or "fundamental guidelines".
ALBANY — At the urging of the energy industry, Gov. David A. Paterson has agreed to reconsider a key rule New York adopted as part of a 10-state pact aimed at reducing the threat of global warming by cutting power plant emissions.
Instead, he chose to use the child of one of his political opponents and in doing so shattered a key rule of polite discourse in campaigns: Kids are off limits.It didn't happen by chance.
As the b-value plays a key rule in present seismic hazard study theories and procedures, the results will be very useful for seismic hazard analysis in Iran.
The effect on different imaging algorithms was reported showing that the focussing algorithm plays a key rule in the final effect on the image.
Adds Boren: "A key rule is that whatever I lay out, I have to put half of it away before I pack".
"A key rule under the Cap code is that if the content is controlled by the marketer, not the vlogger, and is written in exchange for payment (which could be a monetary payment or free items) then it is an advertisement feature and must be labelled as such," it says.
Trump understands a key rule of politics: when you're on the defense, you're losing.
WASHINGTON -- House Republicans took another step Friday toward a repeal of last year's sweeping health care overhaul, as the lower chamber approved a key rule allowing a repeal bill to proceed to a vote.
EU countries would still be responsible for housing refugees who arrive on their territory, preserving a key principle of existing asylum rules known as the Dublin regulation.
