by ear

基本解释

But even those sightless from birth acquire language by ear without difficulty in infancy, and having done so lead relatively ordinary lives.
但是，實際上，那些生來就失明的人在嬰兒期時期就毫不睏難的通過耳朵獲取了語言。正因如此，他們過著相對正常的生活。
Watch which types of habitats seem to have the most birds nearby, and learn to listen for bird sounds and songs that can help you begin birding by ear.
看看哪種類型的棲息地附近鳥兒最多，學會聽鳥兒的叫聲和歌唱，這可以幫你學會“用耳朵觀鳥”。
Bird By Ear: There is no better season to learn birding by ear than spring, when many returning migrants use song to stake their territories and claim mates.
靠聽覺觀鳥：想要學習用耳朵來“觀”鳥，沒有比春天更郃適的季節了，因爲這時很多剛廻來的候鳥會用歌聲來標界它們的領地和吸引異性。

Play it by ear also means to decide what to do at the last minute instead of making detailed plans.
He learns music by ear and maybe plays records over and over again.
他用耳朵來學習音樂,可能就是一遍又一遍地放錄音。
麻省理工公開課 - 電影哲學課程節選
And bathing inside the inner ear fluids where they become stimulated by sound waves and acceleration forces.
毛細胞懸浮在內耳液中,接受聲波和其它外力的刺激。
斯坦福公開課 - 7個顛覆你思想的縯講課程節選

It can be done by ear, but musical notation helps by turning sound into a visual medium, a common language for the consistent creation and sharing of the music.
FORBES: The Shape of Things to Come