[mesmark]

I was working with another teacher who was teaching 'how come'

'How come you are so late?'
'How come he can go but I can't?'
'How come?'

I've taught similar examples to some high school students. However, this book went on to give some examples of embedded sentences that just seemed wierd to me.

'I wonder how come she came.'
'I don't know how come he did that.'

Do these seem strange to anyone else? Is it just that it's a spoken form and looks funny written?