下列不属于生态系统的是（）
A、一群小鸟
B、河流
C、农田
D、泰山
参考答案：A
沿单根神经纤维传导的动作电位的幅度（）
A.不变
B.不断减小
C.不断增大
D.先增大后减小
E.不规则变化
Under criminal law, people who carry and use large numbers of fake banknotes will be sentenced to less than three years in prison.
A．originally
B．occasionally
C．apparently
D．intentionally
