The Internet is a very useful invention for us we can do lots of things at home.A. with

问题补充：

The Internet is a very useful invention for us, we can do lots of things at home.

A. with which

B. with it

C. for which

D. for it

答案：

(答案→)A. with which

B. with it

C. for which

D. for it

解析：考察定语从句。本题定语从句的先行词是a very useful invention,后面的定语从句很完整，故使用关系副词，本题中的关系副词=介词+which,本题中的介词with表示“用”。句意：网络一个很游泳的发明，使用网络我们可以在家里做很多的事情。故A正确。