流行性乙型脑炎最易感动物是()。
A.马
B.牛
C.猪
D.羊
参考答案:A
甲状腺髓样癌可出现()
A.甲胎蛋白(AFP)阳性
B.癌胚抗原(CEA.阳性
C.尿中本-周(Bence-Jones)蛋白定性试验阳性
D.降钙素升高
E.尿中17-羟类固醇明显升高
A ladder 25 feet long is leaning against a wall that is perpendicular to level ground. The bottom of the ladder is 7 feet from the base of the wall. If the top of the ladder slips down 4 feet, how many feet will the bottom of the ladder slip ?()
A.4
B.5
C.8
D.9
E.15