写出比值是4的两个比是( )、( )组成的比例是( )。
8:2;12:3;8:2=12:3(答案不唯一)
I sincerely request the honor of your _______ at my son’s birthday party to be held next Sunday.
A.admission
B.entrance
C.permission
D.presence
神经细胞兴奋阈值最低,最易产生动作电位的部位是()
A.胞体
B.树突
C.轴丘
D.轴突末梢
E.树突末梢