(二)
Lots of people think that dogs just see in black and white. But this is not true. Scientist recently discovered thatdogs do see colors, just not quite the same color that we do.When people see a rainbow, they see purple, blue, blue-green, green, yellow, orange, and red. But when dogs see arainbow, they see gray, blue, gray, yellow-brown, yellow, and yellow-brown. Can you imagine?Dogs see red and green as a single color (yellow-brown) and also blue-green and purple as a single color (gray). Thismeans that if you buy your dog a bright red toys, it will see it as an ugly yellowish brown.Why? Well, a human eyes has three different types of cells that can detect color. Dogs’ eyes, however, have justtwo. This makes the range of colors that they can pick up much more limited.
 (By Jeff James from “I Wonder Why”, Joy Hanline English)
*discover 發現 cell 細胞 range 範圍 limited 有限的 detect 察覺

【題組】34. My brother gives his dog a red and green ball to play. What color is the ball that the dog sees?
(A) Blue-green.
(B) Gray.
(C) Red.
(D) Yellow-brown.