问题
单项选择题
严寒及寒冷地区，采用整体灌注混凝土墩台，其强度等级不应低于（）。
A、C20
B、C25
C、C30
D、C35
答案
参考答案：B
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严寒及寒冷地区，采用整体灌注混凝土墩台，其强度等级不应低于（）。
A、C20
B、C25
C、C30
D、C35
参考答案：B
| During the past three years, the staff members of the Smithsonian Institution’s Family Folklore Project have interviewed hundreds of persons about their family folklore. To prepare for these interviews we drew upon our academic backgrounds in folklore and American studies, and upon our personal backgrounds as members of families, in addition, we reviewed the major instruction guides in genealogy, oral history, family history, and folklore fieldwork. Although these publications were all helpful in some way, no single book was completely adequate since family folklore combines aspects of all the above disciplines. Over time we have developed guidelines and questions that have proven successful for us; we hope that the following suggestions will be helpful to anyone who wishes to collect the folklore of his or her own family. |
According to the passage, which kind of instructional guide was NOT consulted as a source
A．Clinical sociology
B．Genealogy guides
C．Oral history
D．Folklore fieldwork