In order to keep the balance of ecosystem, every possible means to deal with the problems of the over-exploiting of natural resources.
A. has tried
B. has been tried
C. have taken
D. have been taken
网友回答
A. has tried
(答案→)B. has been tried
C. have taken
D. have been taken
解析：考查主谓一致和语态。Means（方式，方法）是一个单复数同形的名词。本题means前面有every修饰，说明本句中的means是一个单数形式，故谓语部分使用单数形式，排除CD。句意：为了保持生态的平衡，每一种可能的方式都已经被使用了来处理过度使用自然资源的问题。故使用被动语态。B项正确。