分期建设、分期投产使用的建设项目，其相应的环境保护设施应当( )。
A．分期验收
B．分期规划
C．集中投产使用
D．集中验收
参考答案：A
Some of the famous pictures _____ taken are on display in the museum.[ ]
A. that was
B. what is
C. they are
D. which were
放射免疫分析中所采用的标记抗原的放化纯度应大于（）
A.75%
B.80%
C.85%
D.90%
E.95%
