A:核糖核酸
B:磷脂
C:ADP
D:淀粉
A. Yes, I do.
B. Mr Li.
C. No, he isn't.
D. He's young.
E. Maths, Chinese and English.
如图中的鱼的实际长度是20m.请你求出这幅图的比例尺.