6 (★★)阅读短文,选择正确的答案。
Dogs are friendly. They can help us. So they are our good friends. Dogs are clever, but they can't see all colours. They are colour-blind. They can only see black, white, grey, yellow and blue. But how can a dog hunt(捕猎) for food? They can hear and smell very well.
()1. The word "colour-blind" means(意思是) "".
A. 失明的 B. 彩色的 C. 色盲的
()2. A dog can see the colour .
A. red B. white C. green
()3. What helps a dog hunt?
A. Ears.
B. Ears and the nose.
C. The nose.

1.C 2.B 3.B

1. 根据短文“they can't see all colours. They are colour-blind”可知，狗不能看到所有颜色，所以“colour-blind”意为“色盲的”，选C；2. 短文提到狗只能看到黑、白、灰、黄、蓝，选项中只有white（白色）符合，选B；3. 短文最后说明狗捕猎靠听觉和嗅觉，对应选项B（耳朵和鼻子）。