____ red is a symbol of warmth, it can s
题型：选择题
问题：
____ red is a symbol of warmth, it can sometimes make people feel uneasy or even frightened.[ ]
A. As
B. Since
C. If
D. While
____ red is a symbol of warmth, it can sometimes make people feel uneasy or even frightened.[ ]
A. As
B. Since
C. If
D. While