Oh, you are so clever! You have______ a solution to the difficult problem!
There is ____ office on the first floor(一楼).
A: Is the pen on the desk?B: ____.
A: Is there a computer in your class?B: ____.
A: ____ boys and girls are there in your class? B: There’re 21 boys and 20 girls.
—___________? —He is Andy’s father.