I have no idea what they're going to say, so I'll have to play it by ear.
我一点不知道他们将会说些什么,所以我只好见机行事。
In the same way, a Russian might fail to see anything amusing in a joke witch would make an Englishman laugh to tears.
同样的道理,一则可以令英国人笑出泪来的笑话,俄国人听了可能觉得没有什么可笑之处。