CONVENTION
（非正式用法,用以引起注意或表示惊讶、有兴趣、生气等）嘿，喂
In informal situations, you say or shout 'hey' to attract someone's attention, or to show surprise, interest, or annoyance.
例句
'Hey! Look out!' shouted Patty...
“嘿！小心点！”帕蒂喊道。
Hey, can I ask you a question?
嘿，我能问你一个问题吗？