疾风知劲草（疾風知勁草）　

◎ 疾风知劲草 jífēng zhī jìncǎo

[the force of the wind tests the strength of the grass;only the toughest grass can stand the strongest wind;the strength of character is tested in a crisis;under strong winds one can know the strength of grass] 比喻在危难时才能显出谁的意志坚强,是经得起考验的人