Human beings are different from animals they can use language as a tool to communicate.A.

问题补充：

Human beings are different from animals they can use language as a tool to communicate.

A. in that

B. for that

C. in which

D. for which

答案：

(答案→)A. in that

B. for that

C. in which

D. for which

解析： 考查原因状语从句，只有A选项能作为状语从句的连接词。 人类不同于动物因为人类可以利用语言来作为交流工具。 选A