落叶知秋

Explanation: Yellow leaves on the ground know that the advent of autumn. Analogy can be predicted by a sign of changing circumstances 　　Usage: Complex sentence; as predicate, object; analogy can be predicted by a sign of development of the situation 　　Source: Tang Geng Song, "recorded text": "puzzled a few cents Monk six decades, the world knows a Yela autumn." Thesaurus:  1 leaves were gone and To know land autumn, The fall of a single leaf ushers in the autumn