“see a man about a dog”别理解成“见一个和狗相关的人”，其正确的含义是不解释而离开；出去一下（尤指上厕所的隐晦说法）；有点急事先行告辞，通常用来作为离开或缺席的借口。

【例句】
I don't know where Tom went. He said he had to see a man about a dog.
我不知道汤姆去哪里了，他说他出去一下。

When John said he was going to see a man about a dog, I thought he would be gone for only a minute.
当约翰说他准备出去一下，我还以为他出去几分钟而已。