胃排空延缓的原因有（）
A.甲亢
B.胃泌素瘤
C.十二指肠溃疡
D.胃下垂
E.糖尿病
参考答案：D
若函数f(x)=|4x-x2|-a的零点个数为3，则a=（ ）。
The teacher asked Tom what he was going to be when he ________ up. [ ]
A. is going to grow
B. grows
C. was going to grow
D. grew
