play it by ear 见机行事，随机应变

　　Let's play it by ear when we get there.

　　到了那儿，我们再见机行事。

　　We should have a plan for tomorrow, or we will have to play it by ear.

　　我们应该准备一个计划，不然只能走一步算一步了。

　　疯狂练习吧！