地理信息可视化理论
参考答案：
研究地图信息的符号化、图形化、形象化及直观性的处理、表达、传递及解译的理论。
预后最差的骨肿瘤是
A．未分化网状细胞肉瘤
B．骨肉瘤
C．原发性软骨肉瘤
D．骨巨细胞瘤Ⅱ级
E．骨纤维肉瘤
Qingdao is a beautiful city. There ______ many people going there ______ vacation every year. [ ]
A. have; on
B. are; at
C. are; on
D. is; for
