Bonjour je besoin de l´aide dans cette exercice:

reformule les phrases suivantes a l´aide de must have been ou can´t have been.
exemple: I think Ruby was a bit proud----- She must have been a bit proud.

1) i don´t think ruby´s parents were very pleased.
2) In my opinion, Ruby´s friends were probably a bit jealous.
3) I think the marshals were unhappy about the publicity.
4) To my mind, there was a crowd phenomenon.