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About ten men in every hundred suffer from color blindness in some way．Women are luckier．Only about one in two hundred is affected in this matter．So some people say it is safer to be driven by women．

There are different forms of color blindness．]n some cases a man may not be able to see deep red．He may think that red，orange and yellow arc all shades（色調）of green．Sometimes a person cannot tell the difference between blue and green．In rare cases an unlucky man may see everything in shades of green--a strange world indeed．

Color blindness in humans is a strange thing to explain．In our eyes there are millions of very small things called “cones”．These help us to see in a bright light and to tell differences between colors．There are also millions of “rods”，but these are used for seeing when it is nearly dark．They show us shapes but no color．

Some insects have favorite colors．Mosquitoes（蚊子）like blue but do not like yellow．A red light will not attract insects，but a blue lamp will．In a similar way humans also have favorite colors．Yet we are lucky．With the aid of the cones in our eyes We can see many beautiful colors by day，and with the aid of the rods we can see shapes at night．One day we may even learn more about the invisible（看不見的）colors around us．

1．With the help of the cones，we can _________．

A．see in a weak light                                   B．tell different shapes

C．kill mosquitoes                                           D．tell orange from yellow

2．Why do some people say it is safer to be driven by women?

A．Women are more careful．

B．There are fewer color blind women．

C．All of them see everything in shades of green．

D．None of them has trouble in recognizing（識別）colors．

3．This passage is mainly about _________．

A．color and its surprising effects                         B．danger caused by color blindness

C．color blindness                                          D．the invisible colors around us