揭示档案中涉及的人物并指明其出处的检索工具是（ ）。
A．人物索引
B．人名索引
C．人名目录
D．人物指南
参考答案：B
"This month our family has used ______ water as we did last month." said Mother.[ ]
A. as twice as much
B. more than twice
C. twice as much as
D. more than twice as much
在射线探伤中，如何辨别铸件中的疏松缺陷？
