[单项选择]In traffic lights, red can only mean stop. But in human languages, limited phonemes can form numerous words which can form unlimited sentences. This is a good illustration of the ______ feature of language.
A. duality
B. displacement
C. arbitrariness
D. productivity

The traffic lights were red when the driver reached them. To the surprise of his passenger, the car did not slow down. Unexpectedly the passenger was thrown forward in the vehicle as the driver put on his brakes at the last moment. The car stopped just in time.
"Sorry, I didn’t notice the light. I thought it was green until I saw that it was the top light which was shining."
This strange story is quite true. About ten men in every hundred are color blind in some way; women are luckier-- only about one in two hundred suffers from color blindness.
In some cases, a man may not be able to see deep red. He may think that red, orange and yellow are all the same as green.
People often like one color more than others. Blue is the color of the sky and sea. Green makes us think of fields and trees. Red is the color of blood and makes some people think of danger. Black is the color of night. In the dark we cannot see what is around us so we ar
A. she drives the car more carefully
B. she sees the road more clearly
C. she can put on the brakes more quickly
D. she has less chance of being color blind