—Look! A book is on the floor. Whose is it?—It ______ be Rick’s. It has his name on it.

— Jack, take more clothes when going camping. It ______ be very cold in the mountains.— Thank you, Mum. I will.

—Will you read me a story, Mummy?—OK. You ________ have one if you go to bed as soon as possible.

—Why are those people gathering in the middle of the street?—I don’t know. There ________ be an accident.

---Dad, must we wait until the light becomes green?---Yes, I’m afraid we ______. That’s the traffic rule.