It wasn't necessary to apologise to Matthew, but I did. (APOLOGISED)
I needn't have apologised to Matthew, but I did.
Was it necessary for you to get your parents' permission to go to the party? (NEED)
Did you need to get your parents' permission to go to the party?
It's important that you keep this as a secret (GOT)
You have got to keep this a secret
He wasn't obliged to pay for his ticket, so he didn't. (HAVE)
He didn't have to pay for his ticket
It wasn't necessary for you to worry about me because I was fine! (WORRIED)
You needn't have worried about me because I was fine!
If you break that window, you'll get into trouble! (NOT)
You must nor break that window or you'll get into trouble!
It was wrong of you to fo that! (SHOULD)
You shouldn't have done that!
It's possible that Jack had a fight with his girlfriend. (MIGHT?
Jack might have had a fight with his gf
