CONVENTION
（交谈中表示同意、疑问、未听清等）嗯，是吗，好吗，什么
Eh is used in writing to represent a noise that people make as a response in conversation, for example to express agreement or to ask for something to be explained or repeated.
例句
Let's talk all about it outside, eh?...
我们出去谈，如何？
'He's um ill in bed.' — 'Eh?' — 'He's ill in bed.'
“嗯，他生病卧床。”——“什么？”——“他生病卧床。”