用作标定滴定溶液浓度的试剂，其纯度应为（）
A.化学纯
B.分析纯
C.实验试剂
D.光谱纯
E.基准级或优级纯
参考答案：E
—I'd prefer to spend this Sunday with my classmates on the seashore.
—________I'm sure you'll have a good weekend.[ ]
A. What a pity!
B. Sounds wonderful.
C. Let me see.
D. Well done!
显微镜下血尿的定义是每个高倍视野尿红细胞超过（）
A.7个
B.5个
C.3个
D.1个
E.10个
