题目

关于核酸的叙述，正确的是（）       A．  蛙的成熟红细胞中不含DNA分子       B．  人体细胞中含有2种核酸，5种碱基       C．  含DNA的原核细胞不会同时含RNA       D．  健那绿染液可以使DNA染成绿色 答案：BThe birth planning policy allows my parents to have a second child because of my disability, but to look after me, they chose ________.A．not to do B．not to have C．not to D．to not have one