The scientists have made possible for us to communicate with each other more easily. A.

问题补充：

The scientists have made possible for us to communicate with each other more easily.

A. it

B. that

C. this

D. them

答案：

(答案→)A. it

B. that

C. this

D. them

解析：考查代词的用法。make it+形容词 for sb to do sth使做某事对某人来说变得......。It是形式宾语，真正的宾语是动词不定式。故选A。