英语习语：

play by ear 随机应变，视情形而定

——Marty, are you doing anything special for your presentation in political science tomorrow? (Marty，你在为明天的政治学演讲准备与众不同的材料吗？)
——Not really, because the class so often turns into a discussion, I've decided to play it by ear. (不。那门课常常最后变成讨论。我决定视情形而定。)

双语例句：
So this is a play by ear as you ones use the term.
所以用你们的术语说，这是一场伺机而动的计划。

When he is coming, I don't know what should be say, I will play by ear at that time.
我没有时间准备这个会议，到时讲到哪里算哪里。

We don't know what to do now, so we must play by ear.
我们不知怎么做，所以必须见机行事。

He had no time to prepare for the party, so he had to play by ear.
他没有时间为这次聚会做准备，只好随机应变了。