表面散有紫黑色斑点的药材是()
A.女贞子
B.决明子
C.五味子
D.牛蒡子
E.吴茱萸
参考答案:D
in a red skirt in the opening ceremony of the 2008 Olympic Games, the little girl Lin Miaoke won the hearts of the people all over the world.
A.Dressed
B.Worn
C.Dressing
D.Wearing
函数z=x2-xy+y2-2x+y的极值为()。
A.不存在
B.2
C.1
D.-1