问题补充：
The Internet and the effectbrought about did a lot of good to our daily life and work. That is to say, the Internet has made a great difference in many aspects.
A. that
B. what
C. which
D. it
答案：
A. that
B. what
C. which
(答案→)D. it
解析：句意：网络及其带来的影响对我们的日常工作和生活很有益。也就是说，网络在许多方面产生了很大的影响。这是定语从句修饰先行词effect, effect在从句中做brought about的宾语，即：the effect that/which the Internet brought about. it指代前面提到的the Internet，此处省略了关系词that/which(做宾语可省略).故D正确。
