The students are doing some cleaning. Some are sweeping the floor, ________ are cleaning the desks and chairs.
--- _____ 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.