The number of the red-crowned cranes will become if we don’t take any action.A. fewer and

问题补充：

The number of the red-crowned cranes will become if we don’t take any action.

A. fewer and fewer

B. less and less

C. smaller and smaller

D. larger and larger

答案：

A. fewer and fewer

B. less and less

(答案→)C. smaller and smaller

D. larger and larger

解析：形容词的比较级用and来连接表示越来越怎样，根据语境可知丹顶鹤的数量会越来越少，如果人类不采取措施的话。