B-21：blunder upon 无意中发现
A:Is this watch yours?
A:这是你的手表吗？
B:No, it isn't mine. I blundered upop it under the sofa. Do you know whose watch it is?
B:不是我的，我在沙发下面拣到的。你知道是谁的吗？
C:Let me have a look. It's mine. I have been looking for it, but just can't find it. It's a present from my father.
C:让我看一看，这是我的手表，我一直在找它，就是找不到。这是我父亲送我的礼物。
B:Well, here you are. Remember to put it in a proper place.
B:噢，给你吧，记得把它放好。
