The approach we propose is a system-oriented methodology for knowledge acquisition. This orientation emphasizes ongoing documentation throughout each cycle and technique applied. Program-wide documentation is suggested, both for the purpose of internal (71) and for later verification and (72) efforts: The documentation system we propose includes a central "knowledge acquisition (73) "which is (74) to reflect knowledge acquisition plans, session nodes, and domain expert participation. Specifically, (75) within the database system include knowledge acquisition forms, which document plans for, and notes from, knowledge acquisition session, domain expert file, and rule content forms.

（71）处填（）。

A．interchange

B．interface

C．communication

D．message

按照《岩土工程勘察规范》规定的岩土参数统计，下列哪项不属于所需的参数？（）

A.标准差

B.变异系数

C.算术平均值

D.方差