腰椎前屈的正常幅度是（）
A.120°
B.160°
C.90°
D.60°
E.30°
参考答案：C
设连续型随机变量X的概率密度f(x)为偶函数，且
则对任意常数
--- What do you think of the film?
--- Fantastic. _______ the children_______ their father likes to see it.
A．Both; and
B．Either; or
C．Not only; but also
D．Neither; nor
则对任意常数