问题
选择题
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
答案：C
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。