“play it by ear”可不是“用耳朵玩”，真实含义是随机应变，见机行事。

【例句】
In dealing with that unpredictable man, you simply cannot follow a prearranged plan, you have to play it by ear.
和那个捉摸不定的人打交道，你简直无法按预定计划行事，只好随机应变。

I've had no time to prepare for this meeting， so I'll have to play it by ear.
我已经没有时间准备这次会议了，所以我会见机行事的。