观察下边漫画，图中蜈蚣寓意着
A．德国
B．俄国
C．日本
D．美国
答案：C
（2分）下列物质属于纯净物的是（ ）
A．铁锈
B．小苏打
C．汽水
D．石油
Green water near coastlines is almost always caused by ______.
A．sand color
B．red pigments in coastal waters
C．blue pigment
D．reflected light and yellow pigment from plant life
