题目

The thief fell to the ground, his left foot _____ and blood _____ down from his mouth. A. breaking; running     B. broken; running C. breaking; run         D. broken; run 答案：B 解析: 考查独立主格结构。foot和break之间是被动关系，blood和run是主动关系。若用A和B分别代表精子细胞中的染色体数和DNA数，则初级精母细胞中的染色体和DNA分别是（   ）A． 2A和3BB． 2A和4BC． 4A和4BD．4A和2B