下列哪项不是视网膜母细胞瘤的常见CT表现()
A.位于眼球壁上
B.肿瘤内团块状钙化
C.肿瘤密度较低
D.肿瘤增强明显
E.肿瘤可向眼球外膨出
参考答案:C
()结构模式较多地出现在由横向合并而形成的企业中。
A.子公司与母公司
B.企业集团
C.分公司与总公司
D.模拟分权
When smaller amounts of additional labor are supplied in response to increases in the wages offered, this is known as the:()
A. substitution effect.
B. income effect.
C. marginal rate of substitution.