利率风险对普通股的影响不像债券和优先股那样没有回旋余地。（　　）

具有社群行为的一组动物是[ ]

A．蜜蜂、白蚁、螳螂

B．蚂蚁、蝗虫、蚊子

C．狒狒、黑猩猩、猕猴

D．大雁、猫头鹰、狼

口呼吸引起的错牙合畸形属于 （）

A.遗传因素

B.环境因素

C.呼吸功能异常

D.全身因素

E.口腔不良习惯

依据WHO标准可疑诊为Crohn病

A．区域性肠道病变，粘膜呈铺路石样改变

B．非连续性肠道病变，伴纵行溃疡

C．全层性炎症性肠道病变伴肿块及狭窄

D．节段性肠道病变，纵行溃疡

E．非连续性肠道病变，全层性炎及非干酪性肉芽肿

Helmut Humm, manager at a large U. S. firm, has just been assigned to the capital budgeting area to replace a person who left suddenly. One of Humm’s first tasks is to calculate the company’s weighted average cost of capital (WACC). Humm finds clear notes on the target capital component weights. Unfortunately, all he can find for the cost of capital components is some handwritten notes. He can make out the numbers, but not the corresponding capital component. So, he has to guess. Here is what Humm deciphered: Target weights : w_d = 30% , w_ps = 20% , w_ce= 50% , where w_d, w_ps, and w_ce are the weights used for debt, preferred stock, and common equity. Cost of components (in no particular order) : 6.0% , 15.0% , and 8.5%.The cost of debt is the after-tax cost. If Hummguesses correctly, the WACC is:（）

A. 9.2%.

B. 11.0%.

C. 9.0%.

每种颜色模式都是（）颜色模型或数学上创建的颜色空间。