国家对生猪实行统一纳税、分别经营和（）
A.定点屠宰
B.集中检疫
C.定点屠宰和集中检疫
D.分散检疫
E.分散宰杀
参考答案：C
按要求完成下列句子。
1. She has some ping-pong balls. (改为否定句)
She _____ any ping-pong balls.
2. I have a baseball. (改为一般疑问句)
_____ _____ have a baseball?
3. She has a good friend. (改为复数)
They _____ three good _____.
4. Tom has three soccers. (对划线部分提问)
_____ soccers does Tom have?
5. Does Mary have an MP4?(作否定回答)
_____, She _____.
检查维生素C中的重金属时，若取样量为1.0g，要求含重金属不得过百万分之十，问应吸取标准铅溶液(每1ml标准铅溶液相当于0.01mg的Pb)多少毫升
A．0.2ml B．0.4ml C．2mlD．1ml E．3ml
