题目

This morning Ms. Green entered our classroom, and _____ us something important about the coming exam, left. A. telling             B. told                     C. having told              D. to tell 答案：C在下列人类疾病中，属于血液遗传病的是（　　） A、白血病B、白化病C、坏血病D、镰刀型细胞贫血症