As we all know the number of Tibetan antelopes(藏羚羊) becoming .A. is; less and lessB. are

问题补充：

As we all know, the number of Tibetan antelopes(藏羚羊) becoming .

A. is; less and less

B. are; less and less

C. is; smaller and smaller

D. are; smaller and smaller

答案：

A. is; less and less

B. are; less and less

(答案→)C. is; smaller and smaller

D. are; smaller and smaller

解析：句意：我们都知道，藏羚羊的数量越来越少。数量the number of的be动词用is;数量的少用small。所以选C。