Well, dogs are colour blind. But that doesn't mean that everything is black and white.

狗都是色盲。但这并不意味着它们眼中只有黑白。

Allan's father is colour blind. He cannot tell green from red. He cannot tell blue from green.

艾伦的父亲是色盲。他分不清绿色和红色。他分不清蓝色和绿色。