to improvise, esp. in a challenging situation when confronted by unknown factors: If you can't come up with a plan, we'll just have to play it by ear.(dictionary.com)つまり、臨機応変に対応することです。そして、play by earはというと、to play (music or a musical instrument) without printed music, as by memory of what one has heard or by unschooled musical instinct.かのモーツアルトが門外不出の曲を一度聴いただけで、おぼえてなおかつ、楽譜に書き写すことができた。。。。のごとく、見よう見まねで、楽器など（かならずしも楽器である必要はありません。）を演奏することを言います。2:45 let's play it by ear. ぶっつけ本番でやろう。
Escorts - SNL
3:58 we will play it by ear and keep chugging along until we either win or lose. 化学療法をそのつどやってみて、がんに勝つか負けるか決着がつくまでやるさ。
Alex Trebek Gives Another Sad Update About His Cancer Fight
練習問題解答
b-2419 play it all by ear
b-3588 played by ear
