核糖体成熟的大小亚基常游离于细胞质中，当大亚基与mRNA结合后，小亚基才结合形成成熟的核糖体。（）
参考答案：错
— Mr Li looks often looks tired and worried?
— So he does. You see it’s not easy to such a big factory.
A．sell
B．win
C．get
D．run
"两票"规定操作监护人应负的安全责任是什么？
