注意：此页面搜索的是所有试题
题目内容
（兰州大学大学英语（4）课程作业）
We also use other forms of communication ________ we may be aware or unaware.
A. to which
B. of which
C. which
D. that
A. to which
B. of which
C. which
D. that
参考答案