– There’s somebody at the door. Who ____ it be? Is it the postman?-- No. It ______ be him. It’s just seven o’clock. It’s too early.
---- How does your father usually go to work? ---- He _____drive a car, but now he _____ there to lose weight.
The math problem is _____ difficult that only _____ students can work it out.
________ fathers are both doctors.
Please __________ the light when you leave the classroom.
When you go _________ the street, you must be careful.