[天壤之别 / 天壤之別, tiān rǎng zhī biéㄊㄧㄢ ㄖㄤˇ ㄓ ㄅㄧㄝˊ] lit. night and day difference (成语 saw); as different as sky and earth; opposite extremes; a world of difference (between them); a far cry from#30597
[きわめる, kiwameru] (v1, vt) (1) (esp. 極める, 窮める) to carry to extremes; to go to the end of something; (2) (esp. 究める) to investigate thoroughly; to master; (P)