— Do you know the boy ______ green?
— Yes,he is Bill.
in
on
at
“in +颜色”表示穿着.....颜色的衣服。
— What color is this orange?
— ______
It's orange.
It's an orange.
They're oranges.
由问句可知对颜色提问，应回答：It's +颜色。