The phrase "a very grave mistake" is correct and usable in written English.
It can be used to emphasize the seriousness of an error or misjudgment.
Example: "Failing to double-check the financial reports was a very grave mistake that could have serious consequences for the company."
Alternatives: "a serious error" or "a significant blunder."
I feel that the Supreme Court made a very grave mistake abolishing this prayer and that you made a very bad error supporting them.
To ignore religion is a very grave mistake and I think the Oslo accords made that mistake".Her husband, Rabbi David Rosen, co-signed an ambitious effort to correct that error: the Alexandria declaration of January 2002, in which rabbis, muftis and top Christians, including George Carey, then Archbishop of Canterbury, agreed that the "holy land" was too sacred to be sullied by blood.
Image caption Recep Tayyip Erdogan called on Saudi Arabia's king to "solve this affair and show leadership" "A very grave mistake is being made in Qatar, isolating a nation in all areas is inhumane and against Islamic values.
I secretly felt that there was no chance in HELL I could do this job and that I had better inform the person who hired me that a very grave mistake had been made.
He said: 'It is a very grave mistake to think that the enjoyment of seeing and searching can be promoted by means of coercion and a sense of duty.' " For Amabile, that comment has added meaning: "I love it, because that is what our educational system is all about". Or, Amabile said, there was poet Sylvia Plath, beset by chronic writer's block and a struggle that ended with her suicide.
Describing that speech as "a very, very grave mistake", Mr Bolton demanded that Mr Annan disavow his deputy.
Not exactly stirring stuff, but such is the nature of the truth that it caused a massive storm in the land of the brave and the free, led by the US Ambassador to the UN, John Bolton, who declared Malloch Brown's speech "a very, very grave mistake by the Deputy Secretary General.... the worst mistake by a senior UN official that I have seen".
"This is a very serious mistake and one that will have grave consequences for the newspaper," he said in a statement that he read to his colleagues.
"Not to understand this would be a very grave historic and political mistake".
