真核生物mRNA前体的加工过程不包括
A．5'末端加帽
B．3'末端加多聚A尾
C．甲基化修饰
D．磷酸化修饰
参考答案：D
从北极上空看地球自转方向是_____________。
Tom didn’t like to study at school and later .
A．dropped in
B．dropped out
C．dropped on
D．dropped off
