B
The red-crowned cranes（丹顶鹤） are birds. They live in China and Russia. They have white bodies and black necks（脖子） and feathers（羽毛）. They also have a “cap” of exposed（裸露的） red skin（皮肤） on the heads. So people call them the red-crowned cranes. The red-crowned crane has one of the most beautiful dances in the bird world. They feed on fish. There are only about 2,000 of these beautiful birds in the world. There are fewer places for them to live in. People need to help them. We should protect their living places and the fish in the same（相同的） waters.
()46. What color are the red-crowned cranes' necks?
A. White.
B. Black.
C. Red.
D. Yellow.
()47. How many colors are mentioned（提及） in the passage?
A. 2.
B. 3.
C. 4.
D. 5.

()48. What do the red-crowned cranes feed on?
A. Fish.
B. Birds.
C. Grass.
D. Plants.
()49. What's the meaning（意思） of the underlined word “protect” in Chinese?
A. 保护
B. 珍惜
C. 扩大
D. 减少
()50. Which of the following is TRUE（正确的）?
A. There are 1,500 kinds of red-crowned cranes.
B. The red-crowned cranes have big living places.
C. We need to protect the red-crowned cranes.
D. The red-crowned cranes only live in China.

46. B 由第三句可知，丹顶鹤的颈部是黑色的。故选 B。
47. B 由第三句、第四句可知，总共提到了 white、black 和 red 三种颜色。故选 B。
48. A 由第七句可知，丹顶鹤吃鱼。故选 A。
49. A 由文中提到“... fewer places for them to live in”可知，它们的栖息地越来越少，我们应该保护它们的栖息地，推测 protect 意为“保护”。故选 A。
50. C 丹顶鹤只有约 2000 只，而不是 1500 种。它们的栖息地越来越少，而不是很大。丹顶鹤不是只在中国，在俄罗斯也有。我们需要保护丹顶鹤是正确的。故选 C。