—Can you help me with my homework , David ? —______________
---- 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.