FCE certainty possibility revision

I don’t know why Irina hasn’t arrived yet. She (have to) stay on late at school, or she (stop) on the way home to see some friends.

Jamie woke up in the night screaming. He (have) a nightmare.

They say it (rain) at the weekend, so maybe we should cancel the football match on Saturday.

I don’t know how old the teacher is, but he looks quite young, so he (be) more than 25.

I think she (be) a really happy person because she’s always smiling and laughing.

Everyone in the class ...(work) incredibly hard because you have all passed the exam!