How to use "explains" in a sentence

It explains everything

After the murders in Berner Street and Mitre Square the streets were too dangerous for the Ripper, which explains why he did not kill in October

My theory explains everything

That explains why I dreamed about the hideous figure of Death in this comic book

That explains the "K.K.K."

'And explains them in the worst possible way.'

'Ah!' said Inspector Slack, 'that explains something Mary said when I spoke to her

'Well, that explains a lot