履霜坚冰

Explanation: Lu: step, step. Stepping on the cream, think of the days of ice is coming. Analogy to see signs of things to be alert to its development. 　　Usage: Complex sentence; as the predicate attribute; metaphor see signs of things to be alert to their development 　　Source: "Book-kun": "sixth day, the ice cream to fulfill. As saying: ice cream shoe, Yin is also the beginning of coagulation; Train To The Road to the ice too." 　　Examples: ~, Yin is also the beginning of coagulation. To tame the Road, to the ice too. ("Two-way Yichuan a book")