广义的肾衰竭分为
A.肾前性、肾性和肾小管坏死
B.肾性、肾后性和肾小管坏死
C.肾前性、肾性和肾后性
D.肾前性、肾小管坏死和肾后性
参考答案:C
Bill ______ the letter from my hand and read it quickly. [ ]
A. pulled
B. took
C. brought
D. sent
袋中有4个红球,3个黑球,从袋中随机取球,设取到一个红球得2分,取到一个黑球得1分,从袋中任取4个球,
(1)求得分X的概率分布列;
(2)求得分大于6分的概率。