猫无法识别颜色。

Cats are not able to perceive color.

人们可以用训练鱼把食物和颜色联系起来的办法教鱼识别颜色。

People can teach fish how to distinguish colors by training fish to relate food with colors.

而杆状体继续对光线做出反应，但由于它不能帮助人们识别颜色，因此所有的物体看上去都是不同形状的黑色、白色或者灰色。

The rods continue to respond toavailable light, but since they cannot see color, so to speak, everything appears to be variousshades of black and white and gray.