-I saw Mark on the playground just now.–No, it _______ be him. He is ill in bed at home.
--- _____ you _____ to ride a motorbike ? --- Yes. But last month I sold it and bought a car.
Science is really _______ useful sucject although it is very difficult.
–We can invite our teachers to the party next weekend. -- Yes. __? I’ll call her at once.
If you don’t understand it, you can ask the teacher , and it’ll become .
--- Could you tell me ? ---Yes, they to the library.