二级社会预防的主要对象是
A．健康人群
B．高危人群
C．患者
D．残疾人群
E．其他
参考答案：B
June 1st is _____ Day and September 10th is _____ Day.[ ]
A. Children's; Teacher's
B. Children's; Teachers
C. Children's; Teachers'
D. Child's; Teacher's
血液细胞染色过深的纠正方法是（）
A.延长染色时间
B.缩短染色时间
C.浓缩染液
D.提高pH值
E.复染
