What is the general meaning of Zhou Enlai’s famous poem in Japan that anticipated his ambition to save the country?

After singing the song of the great river, he turned east. Zhou Enlai September 1917. After singing the great river, he turned east. A sophisticated group of sciences can help the poor in the world. After facing the wall for ten years, trying to break it, it is difficult to be rewarded for crossing the sea and being a hero. Notes: (1) Dajiang: Su Shi's "Nian Nujiao. Chibi Nostalgia" contains the heroic verses "The great river goes eastward, the waves are washed away, and the romantic figures of the ages", here refers to the heroic poems or songs. (2) U-Turn East: Turn around and head east resolutely, referring to crossing eastward to Japan. (3) Sophistication: Profound and meticulous, refers to precise research and in-depth discussion. (4) Qunke: Before and after the May 4th Movement, social sciences were called Qunke, or various disciplines. (5) Help the poor: get rid of social difficulties and save the country from danger. Ji, rescue, aid; Shi, society, country; poverty, extreme distress, on the verge of death. (6) Facing the wall: Sitting facing the wall originally refers to the practice of a master, but here it refers to studying hard and diligently. (7) Breaking the wall: a metaphor for success. This refers to breaking out of the cage and achieving lofty goals. (8) Jump into the sea: jump into the sea and die in the sea. During the Warring States Period, Lu Zhonglian would rather "cross the East China Sea and die" than become a citizen of Qin. In modern times, when Chen Tianhua was studying in Japan, he threw himself into the sea and died for his country in anger to protest against the persecution of overseas students by the Japanese reactionary authorities. Explanation: This poem was written by Zhou Enlai at the age of 19 after finishing high school and on the eve of his eastward journey to Japan. The main idea of ??the poem is: a group of vigorous patriotic young people, after singing inspiring songs, resolutely bid farewell to their motherland and sailed towards Japan in the east. The purpose of studying abroad this time is to learn Japan's advanced science and technology, especially to study profound social sciences, and to explore ways to save the country from danger. We must be determined to face the wall for ten years, resolutely break down the various obstacles and barriers that hinder the country's development, and free the motherland from danger. Even if this grand wish is difficult to realize, then throwing yourself into the sea and sacrificing yourself for the future and interests of the country is indeed a heroic feat. This poem artistically reflects Zhou Enlai's lofty ambition, heroic spirit and dedication to saving the world and the country in his youth. The whole poem is full of spirit, vigorous and heroic, majestic and full of strong artistic appeal.

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