The boys were happily making a snowman, with cold.
A. their faces red
B. their faces were red
C. their faces to be red
D. their faces turned red
网友回答
(答案→)A. their faces red
B. their faces were red
C. their faces to be red
D. their faces turned red
解析：考查独立主格结构。本句在逗号前后没有连词，说明逗号前面的不是一个句子，只是一个短语。排除BD项，这两项都是完整的句子。C项中的to be应该省略。句意：男孩们很开心地堆了一个雪人，他们的脸因为寒冷而变红。their faces red with cold=when their faces was red with cold。故A正确。