People who cannot tell all colors apart are said to be color-blind. Most color-blind people can see yellows and blues, but confuse reds with green. It is very rare for a person to be blind to all colors, but they may see everything in shades of black, white and gray. It is interesting to point out that many color-blind people don’t even realize that they are color-blind, they don’t know that the colors they are seeing and naming are not the actual colors that people with normal vision can see. This can be dangerous when a color-blind person confuses the red and green of a traffic light. Color blindness is thought to be inherited（遗传）and although doctors have tested color blindness, there is no cure to treatment for it. 小题1:There are four cards here, and each has two colors. Which card’s colors do you think a color-blind person can tell correctly? A．Red, Green B．Green, Yellow C．Red, Brown D．Brown, Yellow 小题2:A color-blind person______. A．always knows how color-blind he is B．often gives the wrong name of colors C．see everything as the same color D．can hardly see something of strong colors 小题3:It’s especially dangerous for a color-blind person to cross a street when_____ A．it is crowded B．it is a dark night C．there are no traffic lights at the cross of the streets D．the traffic light turns red 小题4:A person who is color-blind is believed to have something to do with_____. A．his old age B．his poor eyesight C．his parents or grandparents D．his living condition 小题5:Up to now, doctors______. A．have found a way to prevent a person from getting color-blind B．have found a way to free a person from his color blindness C．have been able to tell whether a person is color-blind or not D．have made it quite clear the cause of color blindness