大浪淘沙

Explanation: Amoy: wash with water. Remove impurities. The waves wash sand and gravel in. Analogy in the fierce struggle through trials and screening. 　　Source: Su Yu, "Riptide to the sea," the team through tough training and tests, higher quality, is preserved the essence of Ebb Tide. " 　　Examples: After a tough team training and tests, higher quality, is preserved the essence of ~. (Su Yu "torrent to the sea")