My sister is only two years old, and I have to _____ her on Sunday.
—Look! That man looks like Mr Green. —It can’t be him. He _________ to America.
This is _______ empty bottle. But it is _______useful one.
When you are sleeping, you had better______ all the windows closed.
— Could you tell me ______? — Yes. It’s next to the supermarket.
— Did you see Dr Ma yesterday afternoon? — No. When I got to his office, he ______ already.