исправьте грамматические ошибки (если они тут есть) в нескольких английских предложениях.

the greatest even of 20th century was a man's flight into space.
Yuri Gagarin was a first cosmonaut who is well known around the world.
Yuri Alexeyevich Gagarin was born on March 9th, 1934.
Since childhood Yuri was interested in planes and made toy planes by himself.
he was admitted to pilot school in 1955.
In 1960 Gagarin began to prepare for the flight into space.
On April 12, 1961 Yuri Gagarin was launched into space and spent 108 minutes there.
After that flight, Gagarin has become a Hero for his Country.
Yuri Gagarin is known as a fearless knight of space, the glorious son of the great
Homeland.
He has passed away in 1968 after a short life in the light, but his maneis to be remembered forever on Earth, for it paved a road to the new frontier.

вообщем то вот так будет правильней:) ) были ошибки в грамматическом построении предложения, в артиклях, в датах и т. д и некоторые предложения я полностью переделал, более благозвучно и не так примитивно звучат: )

The greatest event of the 20th century was A MAN'S flight into OUTER space.
Yuri Gagarin is the first cosmonaut WELL-KNOWN in the world.
Yuri Alexeyevich Gagarin was born on the 9th of March, 1934
Since childhood Yuri was interested in planes and made toy planes himself.
In 1955 he entered a school for pilots.
In 1960 Gagarin began to prepare for HIS flight into space.
On April 12, 1961 Yuri Gagarin flew into space and spent 108 minutes there.
Gagarin became THE Hero of our country.
Yuri Gagarin is known as a fearless knight of space, the glorious son of the great
Homeland.
He died in 1968, but he HIS HAME WILL REMAIN forever - on THE Earth and in space