I will definitely pay you back next week.
⇒ I'll definitely pay you back next week.
In a situation like that I would scream until somebody came to help me.
⇒ In a situation like that I'd scream until somebody came to help me.
This is a lovely party, but we have got to go home because of the baby-sitter.
⇒ This is a lovely party, but we've got to go home because of the baby-sitter.
I’ve not heard Sally moving about. She must not be awake yet.
⇒ I’ve not heard Sally moving about. She mustn’t be awake yet.
