Wh- on earth...? 究竟…… 用法透视
特殊疑问句中加上"on earth"可以加强语气，表示强调，有很强的感情色彩，意思是“究竟……；到底……”。另外，也可以用"the hell; in the world"。 支持范例
1. Why on earth do you tell a lie?
你究竟为什么要撒谎？
2. Who on the earth do you think you are anyway?
你究竟认为你是什么人？
3. Where in the world did you find the lost watch?
你到底在哪儿找到那块丢失的手表的？ 会话记忆
A: I've been standing here since half past seven. Where on earth have you been?
我从七点半就一直站在这儿等你。你到底上哪儿去了？
B: I'm terribly sorry I'm late. I just couldn't help it.
真太对不起，我迟到了。不过我实在没办法。
A: It's really very easy saying you're sorry.
说对不起当然很容易。
B: Look, just give me a chance. I can explain it.
你别急，给我个机会，我可以解释！