It is not always easy for the public to see benefit a new invention can be of to human li

问题补充：

It is not always easy for the public to see benefit a new invention can be of to human life.

A. whose

B. what

C. which

D. that

答案：

A. whose

(答案→)B. what

C. which

D. that

解析：考查从句。因为benefit是一个名词，所以应该用what 说明。What benefit应该是放在be 和of之间。句意：对公众来说明白一项新发明对人类生活有什么好处是不容易的。