H+在以下哪种组织的扩散速度最慢？（）
A.A
B.P
C.B
D.F
E.M
参考答案：A
It is not enough only ______the rules of grammar if you want to learn English well.
A．keeping in the mind
B．to keep in mind
C．to keep in your mind
D．keeping in your mind
下列疾病可见视网膜电图中a波和b波均下降，除了（）
A.视网膜色素变性
B.玻璃体出血
C.视网膜脱离
D.脉络膜视网膜炎
E.视网膜中央动脉阻塞
