All possible means but nothing can prevent the buildings .A. has tried; from being pulle

问题补充：

All possible means , but nothing can prevent the buildings .

A. has tried; from being pulled down

B. have tried; from pulling down

C. has been tried; from pulling down

D. have been tried; from being pulled down

答案：

A. has tried; from being pulled down

B. have tried; from pulling down

C. has been tried; from pulling down

(答案→)D. have been tried; from being pulled down

解析：考察主谓一致和prevent的用法。All means谓语动词用复数形式，prevent……from doing sth,阻止……干某事

句意为所有的方法都被尝试过了，但是什么也阻止不了这些建筑物被推倒。