下列哪项不属于婴儿腹泻的病因（）
A.肠道内感染
B.消化系统发育不成熟
C.喂养不当
D.血液中抗体偏低
E.肠道外感染
参考答案：D
锐角A的余弦值为，则角A的范围是（ ）
A．0°＜A＜30°
B．30°＜A＜45°
C．45°＜A＜60°
D．60°＜A＜90°
—How do you like the film?
—There was nothing special-it was only ________. [ ]
A. average
B. usual
C. normal
D. common
