According to the U.S. high government official.

According to the U.S. high government official.

According to a High U.S. Government Official

The 38th summit started in Camp David which is close to Washington on May 18th, and G8 leaders had cooperation that stop to nuclear test of North Korea.

The 38th summit started on May 18th at Camp David, which is near Washington.G8 leaders declared in unison that they would stop any North Korean nuclear tests.

They had conversations about the nuclear problem of North Korea, politics and safe of Syria and so on.

The first part of this sentence before the comma is correct. I don't understand what you're trying to say about Syria.

They agreed on recognition that if North Korea's behavior is provocation, it will stand alone continues more North Korea.

I'm not sure what you meant here.

The Japanese Prime Minister Noda had statement that we have to prospect the North Korea’s provocative behavior so we tell firm intention to them.

Yoshihiko Noda, the Japanese Prime Minister, stated that we have to cotinue to stand firmly against North Korea's provocative behavior so we can communicate our intentions to them.

He also said emphasize that it will be resolve which need Chinese government’s mission.

He also emphasized that this resolve will need the support of the Chinese government.

Prime Minister Russian Medvedev also said that we had agreement about North Korea’s problems.

Dmitry Medvedev, the Russian Prime Minister, also said that the G8 countries were in agreement about North Korea's problems. Note: It sounds more natural to provide the full names off government officials in English.

According to the U.

Replace "the" with "a" in this sentence.

high government official, G8 leaders said that North Korea has to obey the international conventional and if they will not obey it, they will be stand alone all over the world.

According to a high U.s. government official, G8 leaders said that North Korea must obey international law. Furthermore, he said that if North Korea will not obey international law, they will continue to be isolated by the entire world.

However, North Korea is continuing to do the nuclear test after they made a mistake it was discourage missile.

I'm not sure what you meant in this sentence.

They have to have good relationship with all over the world.

They have to have a good relationship with the rest of the world.

If they continue do impolite anything, their government will be destroy by the nation of North Korea.

If the North Korean government continues to act provocatively, it will be destroyed by the North Korean people.