---My pen is yellow._________yours? ---It’s red.
You don’t know ________ I want to see you again. It’s years since I saw you last time.
Do you know who _______ help if you feel stressed?
He ran so fast that he ________ my cup. How careless he is!
— Did you see Dr Ma yesterday afternoon? —When I got to his office, he ______. So we just talked little.
- Someone is knocking at the door. - It ______ be Tom. He is still in the school.