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

问题补充：

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

A. whose

B. what

C. which

D. that

答案：

解析： 考查连接词，句意：对于公众来说看到一项新发明对人类有什么用途并不总是很容易的。什么用途应表达为what use，what 作定语。所以选B。