我不确定该告诉爸爸什么——我只好见机行事了。

I'm not sure what to tell Dad - I'll just have to ___play ___it ___by ___ear.

在去剑桥的路上，我下定决心要随机应变。

On the way to Cambridge, I had made up my mind to ___play ___it ___by ___ear.

既然天气不可预测，我们的野餐计划只好见机行事。

Since the weather is unpredictable, we'll have to ___play ___it ___by ___ear for our picnic plans.