Răspuns:
For 1 the meaning is - when someone are laughing and then they trying to hide that they are laughing.
For 2 the meaning for sure is - when someone are annoyed, embrassed because of somebody, and he's trying to make a complaint perhaps with the police to help him.
For 3 the meaning is - when someone is weak in a do something, when someone are not taking seriosly what they do
For 4 the meaning is - to judge someone else, when he's not guilty, to blame somebody when he have no ties with it!
Explicație:
Take care of you, I hope I helped you as much as I could:)