please proof read it and i try my best fixing my mistake

can you check my puncuation and capitalization. please

On April 9 1917 easter Monday,Canadian soldiers in World war I mounted on their most important offensives of the war.Vimy Ridge,a hill in northan France had been captured by the Germans early in the war and neither the French nor the britsh had been able to rcapture it.The Canadians succeeded where other armies had failed.On that fateful day,more than 3500 canadian soldiers died and another 7000 were injured in the space of just seven hours-but the hill was their's.
Certainly,the battle was a turing point in the war,it was also,however,a turning point in canadas' development as a country.The courageous victory of our soldier's in their first major battle gave canadians the respect of their allies and the lasting sense of prideand self identity.Many believe,this was when Canada came of age as a nation.(among those who espouse this view is the well known historian pierre berton,whose book"Vimy" did much to bring the battle to the prominence it deserves in the Canadian history).
Seventy five years later,the battle was commemorted by prim minister Brain Mulroney,president Francois Mitterand of France,and by 14 surviving veterans who still rember the daywhen so manyof their comrades died.In his speech,Mulroney made the following plea-
"We are here not only to keep faith with those who made the supreme sacrifice,but to rededicate ourselves to the values and ideals that they so courageouslydefended.Their contribution to the Allied victory in the first world war will be celebrrated wherever men and women discuss freedom and the bravery of those who fought to preserve it.

It looks as though a lot of this has been copied from another author.

Do you understand everything that you wrote?

Anyway -- here's the way this should be written:

On April 9, 1917, Easter Monday, Canadian soldiers in World War I mounted their most important offensive of the war. Vimy Ridge,a hill in northern France had been captured by the Germans early in the war and neither the French nor the British had been able to recapture it. The Canadians succeeded where other armies had failed. On that fateful day, more than 3500 Canadian soldiers died, and another 7000 were injured in the space of just seven hours -- but the hill was theirs.
Certainly,the battle was a turning point in the war. It was also, however, a turning point in Canada's development as a country. The courageous victory of our soldiers in their first major battle gave Canadians the respect of their allies and the lasting sense of pride and self identity. Many believe this was when Canada came of age as a nation. Among those who espouse this view is the well-known historian Pierre Berton, whose book "Vimy" did much to bring the battle to the prominence it deserves in the Canadian history.
Seventy-five years later, the battle was commemorated by Prime Minister Brian Mulroney, President Francois Mitterand of France, and by 14 surviving veterans who still remember the day when so many of their comrades died. In his speech,Mulroney made the following plea-
"We are here not only to keep faith with those who made the supreme sacrifice, but to rededicate ourselves to the values and ideals that they so courageously defended. Their contribution to the Allied victory in the first world war will be celebrated wherever men and women discuss freedom and the bravery of those who fought to preserve it."

Sure! Here is the corrected version of your text with punctuation and capitalization:

On April 9, 1917, Easter Monday, Canadian soldiers in World War I mounted one of their most important offensives of the war. Vimy Ridge, a hill in northern France, had been captured by the Germans early in the war, and neither the French nor the British had been able to recapture it. The Canadians succeeded where other armies had failed. On that fateful day, more than 3,500 Canadian soldiers died, and another 7,000 were injured in the space of just seven hours - but the hill was theirs.

Certainly, the battle was a turning point in the war. It was also, however, a turning point in Canada's development as a country. The courageous victory of our soldiers in their first major battle gave Canadians the respect of their allies and a lasting sense of pride and self-identity. Many believe this was when Canada came of age as a nation. (Among those who espouse this view is the well-known historian Pierre Berton, whose book "Vimy" did much to bring the battle to the prominence it deserves in Canadian history.)

Seventy-five years later, the battle was commemorated by Prime Minister Brian Mulroney, President François Mitterrand of France, and by 14 surviving veterans who still remember the day when so many of their comrades died. In his speech, Mulroney made the following plea:

"We are here not only to keep faith with those who made the supreme sacrifice, but to rededicate ourselves to the values and ideals that they so courageously defended. Their contribution to the Allied victory in the First World War will be celebrated wherever men and women discuss freedom and the bravery of those who fought to preserve it."