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。
Indeed they can have a delightful surprise when they find something useful which they did not know they owned.
确实,一旦无意之中从自己的收藏品中找到某件有用的东西时,可以给人一种惊喜的感觉。