12. When millions of rods in our eyes are at work in darkness we can see.
A. shapes only
B. shapes and colors
C. colors only
D. darkness only
出自:大学英语第二册

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块